| blob | 14bd06a860e0cf1201dda29572e6cf6a3287f03e |
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This file contains routines used for analyzing expressions and
13 ** for generating VDBE code that evaluates expressions in SQLite.
14 */
17 /* Forward declarations */
21 /*
22 ** Return the affinity character for a single column of a table.
23 */
27 }
29 /*
30 ** Return the 'affinity' of the expression pExpr if any.
31 **
32 ** If pExpr is a column, a reference to a column via an 'AS' alias,
33 ** or a sub-select with a column as the return value, then the
34 ** affinity of that column is returned. Otherwise, 0x00 is returned,
35 ** indicating no affinity for the expression.
36 **
37 ** i.e. the WHERE clause expressions in the following statements all
38 ** have an affinity:
39 **
40 ** CREATE TABLE t1(a);
41 ** SELECT * FROM t1 WHERE a;
42 ** SELECT a AS b FROM t1 WHERE b;
43 ** SELECT * FROM t1 WHERE (select a from t1);
44 */
53 }
55 #ifndef SQLITE_OMIT_CAST
59 }
60 #endif
63 }
68 );
69 }
71 }
73 /*
74 ** Set the collating sequence for expression pExpr to be the collating
75 ** sequence named by pToken. Return a pointer to a new Expr node that
76 ** implements the COLLATE operator.
77 **
78 ** If a memory allocation error occurs, that fact is recorded in pParse->db
79 ** and the pExpr parameter is returned unchanged.
80 */
86 ){
93 }
94 }
96 }
98 Token s;
102 }
104 /*
105 ** Skip over any TK_COLLATE operators and any unlikely()
106 ** or likelihood() function at the root of an expression.
107 */
118 }
119 }
121 }
123 /*
124 ** Return the collation sequence for the expression pExpr. If
125 ** there is no defined collating sequence, return NULL.
126 **
127 ** See also: sqlite3ExprNNCollSeq()
128 **
129 ** The sqlite3ExprNNCollSeq() works the same exact that it returns the
130 ** default collation if pExpr has no defined collation.
131 **
132 ** The collating sequence might be determined by a COLLATE operator
133 ** or by the presence of a column with a defined collating sequence.
134 ** COLLATE operators take first precedence. Left operands take
135 ** precedence over right operands.
136 */
147 }
151 }
155 ){
156 /* op==TK_REGISTER && p->pTab!=0 happens when pExpr was originally
157 ** a TK_COLUMN but was previously evaluated and cached in a register */
162 }
164 }
170 /* The Expr.x union is never used at the same time as Expr.pRight */
172 /* p->flags holds EP_Collate and p->pLeft->flags does not. And
173 ** p->x.pSelect cannot. So if p->x.pLeft exists, it must hold at
174 ** least one EP_Collate. Thus the following two ALWAYS. */
181 }
182 }
183 }
185 }
188 }
189 }
192 }
194 }
196 /*
197 ** Return the collation sequence for the expression pExpr. If
198 ** there is no defined collating sequence, return a pointer to the
199 ** defautl collation sequence.
200 **
201 ** See also: sqlite3ExprCollSeq()
202 **
203 ** The sqlite3ExprCollSeq() routine works the same except that it
204 ** returns NULL if there is no defined collation.
205 */
211 }
213 /*
214 ** Return TRUE if the two expressions have equivalent collating sequences.
215 */
220 }
222 /*
223 ** pExpr is an operand of a comparison operator. aff2 is the
224 ** type affinity of the other operand. This routine returns the
225 ** type affinity that should be used for the comparison operator.
226 */
230 /* Both sides of the comparison are columns. If one has numeric
231 ** affinity, use that. Otherwise use no affinity.
232 */
237 }
239 /* Neither side of the comparison is a column. Compare the
240 ** results directly.
241 */
244 /* One side is a column, the other is not. Use the columns affinity. */
247 }
248 }
250 /*
251 ** pExpr is a comparison operator. Return the type affinity that should
252 ** be applied to both operands prior to doing the comparison.
253 */
267 }
269 }
271 /*
272 ** pExpr is a comparison expression, eg. '=', '<', IN(...) etc.
273 ** idx_affinity is the affinity of an indexed column. Return true
274 ** if the index with affinity idx_affinity may be used to implement
275 ** the comparison in pExpr.
276 */
286 }
287 }
289 /*
290 ** Return the P5 value that should be used for a binary comparison
291 ** opcode (OP_Eq, OP_Ge etc.) used to compare pExpr1 and pExpr2.
292 */
297 }
299 /*
300 ** Return a pointer to the collation sequence that should be used by
301 ** a binary comparison operator comparing pLeft and pRight.
302 **
303 ** If the left hand expression has a collating sequence type, then it is
304 ** used. Otherwise the collation sequence for the right hand expression
305 ** is used, or the default (BINARY) if neither expression has a collating
306 ** type.
307 **
308 ** Argument pRight (but not pLeft) may be a null pointer. In this case,
309 ** it is not considered.
310 */
314 Expr *pRight
315 ){
326 }
327 }
329 }
331 /*
332 ** Generate code for a comparison operator.
333 */
342 ){
353 }
355 /*
356 ** Return true if expression pExpr is a vector, or false otherwise.
357 **
358 ** A vector is defined as any expression that results in two or more
359 ** columns of result. Every TK_VECTOR node is an vector because the
360 ** parser will not generate a TK_VECTOR with fewer than two entries.
361 ** But a TK_SELECT might be either a vector or a scalar. It is only
362 ** considered a vector if it has two or more result columns.
363 */
366 }
368 /*
369 ** If the expression passed as the only argument is of type TK_VECTOR
370 ** return the number of expressions in the vector. Or, if the expression
371 ** is a sub-select, return the number of columns in the sub-select. For
372 ** any other type of expression, return 1.
373 */
383 }
384 }
386 /*
387 ** Return a pointer to a subexpression of pVector that is the i-th
388 ** column of the vector (numbered starting with 0). The caller must
389 ** ensure that i is within range.
390 **
391 ** If pVector is really a scalar (and "scalar" here includes subqueries
392 ** that return a single column!) then return pVector unmodified.
393 **
394 ** pVector retains ownership of the returned subexpression.
395 **
396 ** If the vector is a (SELECT ...) then the expression returned is
397 ** just the expression for the i-th term of the result set, and may
398 ** not be ready for evaluation because the table cursor has not yet
399 ** been positioned.
400 */
409 }
410 }
412 }
414 /*
415 ** Compute and return a new Expr object which when passed to
416 ** sqlite3ExprCode() will generate all necessary code to compute
417 ** the iField-th column of the vector expression pVector.
418 **
419 ** It is ok for pVector to be a scalar (as long as iField==0).
420 ** In that case, this routine works like sqlite3ExprDup().
421 **
422 ** The caller owns the returned Expr object and is responsible for
423 ** ensuring that the returned value eventually gets freed.
424 **
425 ** The caller retains ownership of pVector. If pVector is a TK_SELECT,
426 ** then the returned object will reference pVector and so pVector must remain
427 ** valid for the life of the returned object. If pVector is a TK_VECTOR
428 ** or a scalar expression, then it can be deleted as soon as this routine
429 ** returns.
430 **
431 ** A trick to cause a TK_SELECT pVector to be deleted together with
432 ** the returned Expr object is to attach the pVector to the pRight field
433 ** of the returned TK_SELECT_COLUMN Expr object.
434 */
439 ){
443 /* The TK_SELECT_COLUMN Expr node:
444 **
445 ** pLeft: pVector containing TK_SELECT. Not deleted.
446 ** pRight: not used. But recursively deleted.
447 ** iColumn: Index of a column in pVector
448 ** iTable: 0 or the number of columns on the LHS of an assignment
449 ** pLeft->iTable: First in an array of register holding result, or 0
450 ** if the result is not yet computed.
451 **
452 ** sqlite3ExprDelete() specifically skips the recursive delete of
453 ** pLeft on TK_SELECT_COLUMN nodes. But pRight is followed, so pVector
454 ** can be attached to pRight to cause this node to take ownership of
455 ** pVector. Typically there will be multiple TK_SELECT_COLUMN nodes
456 ** with the same pLeft pointer to the pVector, but only one of them
457 ** will own the pVector.
458 */
463 }
468 }
470 }
472 /*
473 ** If expression pExpr is of type TK_SELECT, generate code to evaluate
474 ** it. Return the register in which the result is stored (or, if the
475 ** sub-select returns more than one column, the first in an array
476 ** of registers in which the result is stored).
477 **
478 ** If pExpr is not a TK_SELECT expression, return 0.
479 */
482 #ifndef SQLITE_OMIT_SUBQUERY
485 }
486 #endif
488 }
490 /*
491 ** Argument pVector points to a vector expression - either a TK_VECTOR
492 ** or TK_SELECT that returns more than one column. This function returns
493 ** the register number of a register that contains the value of
494 ** element iField of the vector.
495 **
496 ** If pVector is a TK_SELECT expression, then code for it must have
497 ** already been generated using the exprCodeSubselect() routine. In this
498 ** case parameter regSelect should be the first in an array of registers
499 ** containing the results of the sub-select.
500 **
501 ** If pVector is of type TK_VECTOR, then code for the requested field
502 ** is generated. In this case (*pRegFree) may be set to the number of
503 ** a temporary register to be freed by the caller before returning.
504 **
505 ** Before returning, output parameter (*ppExpr) is set to point to the
506 ** Expr object corresponding to element iElem of the vector.
507 */
515 ){
521 }
525 }
528 }
530 /*
531 ** Expression pExpr is a comparison between two vector values. Compute
532 ** the result of the comparison (1, 0, or NULL) and write that
533 ** result into register dest.
534 **
535 ** The caller must satisfy the following preconditions:
536 **
537 ** if pExpr->op==TK_IS: op==TK_EQ and p5==SQLITE_NULLEQ
538 ** if pExpr->op==TK_ISNOT: op==TK_NE and p5==SQLITE_NULLEQ
539 ** otherwise: op==pExpr->op and p5==0
540 */
546 u8 p5 /* SQLITE_NULLEQ or zero */
547 ){
561 }
566 );
599 }
614 }
615 }
617 }
619 #if SQLITE_MAX_EXPR_DEPTH>0
620 /*
621 ** Check that argument nHeight is less than or equal to the maximum
622 ** expression depth allowed. If it is not, leave an error message in
623 ** pParse.
624 */
631 );
633 }
635 }
637 /* The following three functions, heightOfExpr(), heightOfExprList()
638 ** and heightOfSelect(), are used to determine the maximum height
639 ** of any expression tree referenced by the structure passed as the
640 ** first argument.
641 **
642 ** If this maximum height is greater than the current value pointed
643 ** to by pnHeight, the second parameter, then set *pnHeight to that
644 ** value.
645 */
650 }
651 }
652 }
658 }
659 }
660 }
670 }
671 }
673 /*
674 ** Set the Expr.nHeight variable in the structure passed as an
675 ** argument. An expression with no children, Expr.pList or
676 ** Expr.pSelect member has a height of 1. Any other expression
677 ** has a height equal to the maximum height of any other
678 ** referenced Expr plus one.
679 **
680 ** Also propagate EP_Propagate flags up from Expr.x.pList to Expr.flags,
681 ** if appropriate.
682 */
692 }
694 }
696 /*
697 ** Set the Expr.nHeight variable using the exprSetHeight() function. If
698 ** the height is greater than the maximum allowed expression depth,
699 ** leave an error in pParse.
700 **
701 ** Also propagate all EP_Propagate flags from the Expr.x.pList into
702 ** Expr.flags.
703 */
708 }
710 /*
711 ** Return the maximum height of any expression tree referenced
712 ** by the select statement passed as an argument.
713 */
718 }
720 /*
721 ** Propagate all EP_Propagate flags from the Expr.x.pList into
722 ** Expr.flags.
723 */
727 }
728 }
729 #define exprSetHeight(y)
732 /*
733 ** This routine is the core allocator for Expr nodes.
734 **
735 ** Construct a new expression node and return a pointer to it. Memory
736 ** for this node and for the pToken argument is a single allocation
737 ** obtained from sqlite3DbMalloc(). The calling function
738 ** is responsible for making sure the node eventually gets freed.
739 **
740 ** If dequote is true, then the token (if it exists) is dequoted.
741 ** If dequote is false, no dequoting is performed. The deQuote
742 ** parameter is ignored if pToken is NULL or if the token does not
743 ** appear to be quoted. If the quotes were of the form "..." (double-quotes)
744 ** then the EP_DblQuoted flag is set on the expression node.
745 **
746 ** Special case: If op==TK_INTEGER and pToken points to a string that
747 ** can be translated into a 32-bit integer, then the token is not
748 ** stored in u.zToken. Instead, the integer values is written
749 ** into u.iValue and the EP_IntValue flag is set. No extra storage
750 ** is allocated to hold the integer text and the dequote flag is ignored.
751 */
757 ){
768 }
769 }
787 }
788 }
789 }
790 #if SQLITE_MAX_EXPR_DEPTH>0
792 #endif
793 }
795 }
797 /*
798 ** Allocate a new expression node from a zero-terminated token that has
799 ** already been dequoted.
800 */
805 ){
806 Token x;
810 }
812 /*
813 ** Attach subtrees pLeft and pRight to the Expr node pRoot.
814 **
815 ** If pRoot==NULL that means that a memory allocation error has occurred.
816 ** In that case, delete the subtrees pLeft and pRight.
817 */
822 Expr *pRight
823 ){
832 }
836 }
838 }
839 }
841 /*
842 ** Allocate an Expr node which joins as many as two subtrees.
843 **
844 ** One or both of the subtrees can be NULL. Return a pointer to the new
845 ** Expr node. Or, if an OOM error occurs, set pParse->db->mallocFailed,
846 ** free the subtrees and return NULL.
847 */
853 ){
856 /* Take advantage of short-circuit false optimization for AND */
864 }
866 }
869 }
871 }
873 /*
874 ** Add pSelect to the Expr.x.pSelect field. Or, if pExpr is NULL (due
875 ** do a memory allocation failure) then delete the pSelect object.
876 */
885 }
886 }
889 /*
890 ** If the expression is always either TRUE or FALSE (respectively),
891 ** then return 1. If one cannot determine the truth value of the
892 ** expression at compile-time return 0.
893 **
894 ** This is an optimization. If is OK to return 0 here even if
895 ** the expression really is always false or false (a false negative).
896 ** But it is a bug to return 1 if the expression might have different
897 ** boolean values in different circumstances (a false positive.)
898 **
899 ** Note that if the expression is part of conditional for a
900 ** LEFT JOIN, then we cannot determine at compile-time whether or not
901 ** is it true or false, so always return 0.
902 */
908 }
914 }
916 /*
917 ** Join two expressions using an AND operator. If either expression is
918 ** NULL, then just return the other expression.
919 **
920 ** If one side or the other of the AND is known to be false, then instead
921 ** of returning an AND expression, just return a constant expression with
922 ** a value of false.
923 */
937 }
938 }
940 /*
941 ** Construct a new expression node for a function with multiple
942 ** arguments.
943 */
952 }
958 }
960 /*
961 ** Assign a variable number to an expression that encodes a wildcard
962 ** in the original SQL statement.
963 **
964 ** Wildcards consisting of a single "?" are assigned the next sequential
965 ** variable number.
966 **
967 ** Wildcards of the form "?nnn" are assigned the number "nnn". We make
968 ** sure "nnn" is not too big to avoid a denial of service attack when
969 ** the SQL statement comes from an external source.
970 **
971 ** Wildcards of the form ":aaa", "@aaa", or "$aaa" are assigned the same number
972 ** as the previous instance of the same wildcard. Or if this is the first
973 ** instance of the wildcard, the next sequential variable number is
974 ** assigned.
975 */
979 ynVar x;
988 /* Wildcard of the form "?". Assign the next variable number */
994 /* Wildcard of the form "?nnn". Convert "nnn" to an integer and
995 ** use it as the variable number */
996 i64 i;
1003 }
1012 }
1019 }
1021 /* Wildcards like ":aaa", "$aaa" or "@aaa". Reuse the same variable
1022 ** number as the prior appearance of the same name, or if the name
1023 ** has never appeared before, reuse the same variable number
1024 */
1029 }
1030 }
1033 }
1034 }
1038 }
1039 }
1041 /*
1042 ** Recursively delete an expression tree.
1043 */
1046 /* Sanity check: Assert that the IntValue is non-negative if it exists */
1048 #ifdef SQLITE_DEBUG
1053 }
1054 #endif
1056 /* The Expr.x union is never used at the same time as Expr.pRight */
1065 }
1066 }
1070 }
1071 }
1074 }
1076 /*
1077 ** Return the number of bytes allocated for the expression structure
1078 ** passed as the first argument. This is always one of EXPR_FULLSIZE,
1079 ** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
1080 */
1085 }
1087 /*
1088 ** The dupedExpr*Size() routines each return the number of bytes required
1089 ** to store a copy of an expression or expression tree. They differ in
1090 ** how much of the tree is measured.
1091 **
1092 ** dupedExprStructSize() Size of only the Expr structure
1093 ** dupedExprNodeSize() Size of Expr + space for token
1094 ** dupedExprSize() Expr + token + subtree components
1095 **
1096 ***************************************************************************
1097 **
1098 ** The dupedExprStructSize() function returns two values OR-ed together:
1099 ** (1) the space required for a copy of the Expr structure only and
1100 ** (2) the EP_xxx flags that indicate what the structure size should be.
1101 ** The return values is always one of:
1102 **
1103 ** EXPR_FULLSIZE
1104 ** EXPR_REDUCEDSIZE | EP_Reduced
1105 ** EXPR_TOKENONLYSIZE | EP_TokenOnly
1106 **
1107 ** The size of the structure can be found by masking the return value
1108 ** of this routine with 0xfff. The flags can be found by masking the
1109 ** return value with EP_Reduced|EP_TokenOnly.
1110 **
1111 ** Note that with flags==EXPRDUP_REDUCE, this routines works on full-size
1112 ** (unreduced) Expr objects as they or originally constructed by the parser.
1113 ** During expression analysis, extra information is computed and moved into
1114 ** later parts of teh Expr object and that extra information might get chopped
1115 ** off if the expression is reduced. Note also that it does not work to
1116 ** make an EXPRDUP_REDUCE copy of a reduced expression. It is only legal
1117 ** to reduce a pristine expression tree from the parser. The implementation
1118 ** of dupedExprStructSize() contain multiple assert() statements that attempt
1119 ** to enforce this constraint.
1120 */
1138 }
1139 }
1141 }
1143 /*
1144 ** This function returns the space in bytes required to store the copy
1145 ** of the Expr structure and a copy of the Expr.u.zToken string (if that
1146 ** string is defined.)
1147 */
1152 }
1154 }
1156 /*
1157 ** Return the number of bytes required to create a duplicate of the
1158 ** expression passed as the first argument. The second argument is a
1159 ** mask containing EXPRDUP_XXX flags.
1160 **
1161 ** The value returned includes space to create a copy of the Expr struct
1162 ** itself and the buffer referred to by Expr.u.zToken, if any.
1163 **
1164 ** If the EXPRDUP_REDUCE flag is set, then the return value includes
1165 ** space to duplicate all Expr nodes in the tree formed by Expr.pLeft
1166 ** and Expr.pRight variables (but not for any structures pointed to or
1167 ** descended from the Expr.x.pList or Expr.x.pSelect variables).
1168 */
1175 }
1176 }
1178 }
1180 /*
1181 ** This function is similar to sqlite3ExprDup(), except that if pzBuffer
1182 ** is not NULL then *pzBuffer is assumed to point to a buffer large enough
1183 ** to store the copy of expression p, the copies of p->u.zToken
1184 ** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
1185 ** if any. Before returning, *pzBuffer is set to the first byte past the
1186 ** portion of the buffer copied into by this function.
1187 */
1198 /* Figure out where to write the new Expr structure. */
1205 }
1209 /* Set nNewSize to the size allocated for the structure pointed to
1210 ** by pNew. This is either EXPR_FULLSIZE, EXPR_REDUCEDSIZE or
1211 ** EXPR_TOKENONLYSIZE. nToken is set to the number of bytes consumed
1212 ** by the copy of the p->u.zToken string (if any).
1213 */
1221 }
1230 }
1231 }
1233 /* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
1238 /* Copy the p->u.zToken string, if any. */
1242 }
1245 /* Fill in the pNew->x.pSelect or pNew->x.pList member. */
1250 }
1251 }
1253 /* Fill in pNew->pLeft and pNew->pRight. */
1261 }
1264 }
1273 }
1275 }
1276 }
1277 }
1279 }
1281 /*
1282 ** Create and return a deep copy of the object passed as the second
1283 ** argument. If an OOM condition is encountered, NULL is returned
1284 ** and the db->mallocFailed flag set.
1285 */
1286 #ifndef SQLITE_OMIT_CTE
1299 }
1300 }
1301 }
1303 }
1304 #else
1305 # define withDup(x,y) 0
1306 #endif
1308 /*
1309 ** The following group of routines make deep copies of expressions,
1310 ** expression lists, ID lists, and select statements. The copies can
1311 ** be deleted (by being passed to their respective ...Delete() routines)
1312 ** without effecting the originals.
1313 **
1314 ** The expression list, ID, and source lists return by sqlite3ExprListDup(),
1315 ** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded
1316 ** by subsequent calls to sqlite*ListAppend() routines.
1317 **
1318 ** Any tables that the SrcList might point to are not duplicated.
1319 **
1320 ** The flags parameter contains a combination of the EXPRDUP_XXX flags.
1321 ** If the EXPRDUP_REDUCE flag is set, then the structure returned is a
1322 ** truncated version of the usual Expr structure that will be stored as
1323 ** part of the in-memory representation of the database schema.
1324 */
1328 }
1348 ){
1359 }
1360 }
1367 }
1369 }
1371 /*
1372 ** If cursors, triggers, views and subqueries are all omitted from
1373 ** the build, then none of the following routines, except for
1374 ** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
1375 ** called with a NULL argument.
1376 */
1377 #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
1378 || !defined(SQLITE_OMIT_SUBQUERY)
1403 }
1408 }
1412 }
1417 }
1419 }
1432 }
1433 /* Note that because the size of the allocation for p->a[] is not
1434 ** necessarily a power of two, sqlite3IdListAppend() may not be called
1435 ** on the duplicate created by this function. */
1441 }
1443 }
1475 }
1478 }
1479 #else
1483 }
1484 #endif
1487 /*
1488 ** Add a new element to the end of an expression list. If pList is
1489 ** initially NULL, then create a new expression list.
1490 **
1491 ** The pList argument must be either NULL or a pointer to an ExprList
1492 ** obtained from a prior call to sqlite3ExprListAppend(). This routine
1493 ** may not be used with an ExprList obtained from sqlite3ExprListDup().
1494 ** Reason: This routine assumes that the number of slots in pList->a[]
1495 ** is a power of two. That is true for sqlite3ExprListAppend() returns
1496 ** but is not necessarily true from the return value of sqlite3ExprListDup().
1497 **
1498 ** If a memory allocation error occurs, the entire list is freed and
1499 ** NULL is returned. If non-NULL is returned, then it is guaranteed
1500 ** that the new entry was successfully appended.
1501 */
1506 ){
1514 }
1522 }
1524 }
1532 no_mem:
1533 /* Avoid leaking memory if malloc has failed. */
1537 }
1539 /*
1540 ** pColumns and pExpr form a vector assignment which is part of the SET
1541 ** clause of an UPDATE statement. Like this:
1542 **
1543 ** (a,b,c) = (expr1,expr2,expr3)
1544 ** Or: (a,b,c) = (SELECT x,y,z FROM ....)
1545 **
1546 ** For each term of the vector assignment, append new entries to the
1547 ** expression list pList. In the case of a subquery on the RHS, append
1548 ** TK_SELECT_COLUMN expressions.
1549 */
1555 ){
1560 /* pColumns can only be NULL due to an OOM but an OOM will cause an
1561 ** exit prior to this routine being invoked */
1565 /* If the RHS is a vector, then we can immediately check to see that
1566 ** the size of the RHS and LHS match. But if the RHS is a SELECT,
1567 ** wildcards ("*") in the result set of the SELECT must be expanded before
1568 ** we can do the size check, so defer the size check until code generation.
1569 */
1574 }
1583 }
1584 }
1591 /* Store the SELECT statement in pRight so it will be deleted when
1592 ** sqlite3ExprListDelete() is called */
1596 /* Remember the size of the LHS in iTable so that we can check that
1597 ** the RHS and LHS sizes match during code generation. */
1599 }
1601 vector_append_error:
1605 }
1607 /*
1608 ** Set the sort order for the last element on the given ExprList.
1609 */
1617 }
1619 }
1621 /*
1622 ** Set the ExprList.a[].zName element of the most recently added item
1623 ** on the expression list.
1624 **
1625 ** pList might be NULL following an OOM error. But pName should never be
1626 ** NULL. If a memory allocation fails, the pParse->db->mallocFailed flag
1627 ** is set.
1628 */
1634 ){
1643 }
1644 }
1646 /*
1647 ** Set the ExprList.a[].zSpan element of the most recently added item
1648 ** on the expression list.
1649 **
1650 ** pList might be NULL following an OOM error. But pSpan should never be
1651 ** NULL. If a memory allocation fails, the pParse->db->mallocFailed flag
1652 ** is set.
1653 */
1659 ){
1667 }
1668 }
1670 /*
1671 ** If the expression list pEList contains more than iLimit elements,
1672 ** leave an error message in pParse.
1673 */
1678 ){
1684 }
1685 }
1687 /*
1688 ** Delete an entire expression list.
1689 */
1698 pItem++;
1701 }
1704 }
1706 /*
1707 ** Return the bitwise-OR of all Expr.flags fields in the given
1708 ** ExprList.
1709 */
1718 }
1720 }
1722 /*
1723 ** This is a SELECT-node callback for the expression walker that
1724 ** always "fails". By "fail" in this case, we mean set
1725 ** pWalker->eCode to zero and abort.
1726 **
1727 ** This callback is used by multiple expression walkers.
1728 */
1733 }
1735 /*
1736 ** If the input expression is an ID with the name "true" or "false"
1737 ** then convert it into an TK_TRUEFALSE term. Return non-zero if
1738 ** the conversion happened, and zero if the expression is unaltered.
1739 */
1744 ){
1747 }
1749 }
1751 /*
1752 ** The argument must be a TK_TRUEFALSE Expr node. Return 1 if it is TRUE
1753 ** and 0 if it is FALSE.
1754 */
1760 }
1763 /*
1764 ** These routines are Walker callbacks used to check expressions to
1765 ** see if they are "constant" for some definition of constant. The
1766 ** Walker.eCode value determines the type of "constant" we are looking
1767 ** for.
1768 **
1769 ** These callback routines are used to implement the following:
1770 **
1771 ** sqlite3ExprIsConstant() pWalker->eCode==1
1772 ** sqlite3ExprIsConstantNotJoin() pWalker->eCode==2
1773 ** sqlite3ExprIsTableConstant() pWalker->eCode==3
1774 ** sqlite3ExprIsConstantOrFunction() pWalker->eCode==4 or 5
1775 **
1776 ** In all cases, the callbacks set Walker.eCode=0 and abort if the expression
1777 ** is found to not be a constant.
1778 **
1779 ** The sqlite3ExprIsConstantOrFunction() is used for evaluating expressions
1780 ** in a CREATE TABLE statement. The Walker.eCode value is 5 when parsing
1781 ** an existing schema and 4 when processing a new statement. A bound
1782 ** parameter raises an error for new statements, but is silently converted
1783 ** to NULL for existing schemas. This allows sqlite_master tables that
1784 ** contain a bound parameter because they were generated by older versions
1785 ** of SQLite to be parsed by newer versions of SQLite without raising a
1786 ** malformed schema error.
1787 */
1790 /* If pWalker->eCode is 2 then any term of the expression that comes from
1791 ** the ON or USING clauses of a left join disqualifies the expression
1792 ** from being considered constant. */
1796 }
1799 /* Consider functions to be constant if all their arguments are constant
1800 ** and either pWalker->eCode==4 or 5 or the function has the
1801 ** SQLITE_FUNC_CONST flag. */
1808 }
1810 /* Convert "true" or "false" in a DEFAULT clause into the
1811 ** appropriate TK_TRUEFALSE operator */
1814 }
1815 /* Fall thru */
1825 }
1826 /* Fall through */
1833 /* Silently convert bound parameters that appear inside of CREATE
1834 ** statements into a NULL when parsing the CREATE statement text out
1835 ** of the sqlite_master table */
1838 /* A bound parameter in a CREATE statement that originates from
1839 ** sqlite3_prepare() causes an error */
1842 }
1843 /* Fall through */
1848 }
1849 }
1851 Walker w;
1855 #ifdef SQLITE_DEBUG
1857 #endif
1861 }
1863 /*
1864 ** Walk an expression tree. Return non-zero if the expression is constant
1865 ** and 0 if it involves variables or function calls.
1866 **
1867 ** For the purposes of this function, a double-quoted string (ex: "abc")
1868 ** is considered a variable but a single-quoted string (ex: 'abc') is
1869 ** a constant.
1870 */
1873 }
1875 /*
1876 ** Walk an expression tree. Return non-zero if the expression is constant
1877 ** that does no originate from the ON or USING clauses of a join.
1878 ** Return 0 if it involves variables or function calls or terms from
1879 ** an ON or USING clause.
1880 */
1883 }
1885 /*
1886 ** Walk an expression tree. Return non-zero if the expression is constant
1887 ** for any single row of the table with cursor iCur. In other words, the
1888 ** expression must not refer to any non-deterministic function nor any
1889 ** table other than iCur.
1890 */
1893 }
1896 /*
1897 ** sqlite3WalkExpr() callback used by sqlite3ExprIsConstantOrGroupBy().
1898 */
1903 /* Check if pExpr is identical to any GROUP BY term. If so, consider
1904 ** it constant. */
1911 }
1912 }
1913 }
1915 /* Check if pExpr is a sub-select. If so, consider it variable. */
1919 }
1922 }
1924 /*
1925 ** Walk the expression tree passed as the first argument. Return non-zero
1926 ** if the expression consists entirely of constants or copies of terms
1927 ** in pGroupBy that sort with the BINARY collation sequence.
1928 **
1929 ** This routine is used to determine if a term of the HAVING clause can
1930 ** be promoted into the WHERE clause. In order for such a promotion to work,
1931 ** the value of the HAVING clause term must be the same for all members of
1932 ** a "group". The requirement that the GROUP BY term must be BINARY
1933 ** assumes that no other collating sequence will have a finer-grained
1934 ** grouping than binary. In other words (A=B COLLATE binary) implies
1935 ** A=B in every other collating sequence. The requirement that the
1936 ** GROUP BY be BINARY is stricter than necessary. It would also work
1937 ** to promote HAVING clauses that use the same alternative collating
1938 ** sequence as the GROUP BY term, but that is much harder to check,
1939 ** alternative collating sequences are uncommon, and this is only an
1940 ** optimization, so we take the easy way out and simply require the
1941 ** GROUP BY to use the BINARY collating sequence.
1942 */
1944 Walker w;
1952 }
1954 /*
1955 ** Walk an expression tree. Return non-zero if the expression is constant
1956 ** or a function call with constant arguments. Return and 0 if there
1957 ** are any variables.
1958 **
1959 ** For the purposes of this function, a double-quoted string (ex: "abc")
1960 ** is considered a variable but a single-quoted string (ex: 'abc') is
1961 ** a constant.
1962 */
1966 }
1968 #ifdef SQLITE_ENABLE_CURSOR_HINTS
1969 /*
1970 ** Walk an expression tree. Return 1 if the expression contains a
1971 ** subquery of some kind. Return 0 if there are no subqueries.
1972 */
1974 Walker w;
1978 #ifdef SQLITE_DEBUG
1980 #endif
1983 }
1984 #endif
1986 /*
1987 ** If the expression p codes a constant integer that is small enough
1988 ** to fit in a 32-bit integer, return 1 and put the value of the integer
1989 ** in *pValue. If the expression is not an integer or if it is too big
1990 ** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
1991 */
1996 /* If an expression is an integer literal that fits in a signed 32-bit
1997 ** integer, then the EP_IntValue flag will have already been set */
2004 }
2009 }
2016 }
2018 }
2020 }
2022 }
2024 /*
2025 ** Return FALSE if there is no chance that the expression can be NULL.
2026 **
2027 ** If the expression might be NULL or if the expression is too complex
2028 ** to tell return TRUE.
2029 **
2030 ** This routine is used as an optimization, to skip OP_IsNull opcodes
2031 ** when we know that a value cannot be NULL. Hence, a false positive
2032 ** (returning TRUE when in fact the expression can never be NULL) might
2033 ** be a small performance hit but is otherwise harmless. On the other
2034 ** hand, a false negative (returning FALSE when the result could be NULL)
2035 ** will likely result in an incorrect answer. So when in doubt, return
2036 ** TRUE.
2037 */
2039 u8 op;
2055 }
2056 }
2058 /*
2059 ** Return TRUE if the given expression is a constant which would be
2060 ** unchanged by OP_Affinity with the affinity given in the second
2061 ** argument.
2062 **
2063 ** This routine is used to determine if the OP_Affinity operation
2064 ** can be omitted. When in doubt return FALSE. A false negative
2065 ** is harmless. A false positive, however, can result in the wrong
2066 ** answer.
2067 */
2069 u8 op;
2077 }
2080 }
2083 }
2086 }
2091 }
2094 }
2095 }
2096 }
2098 /*
2099 ** Return TRUE if the given string is a row-id column name.
2100 */
2106 }
2108 /*
2109 ** pX is the RHS of an IN operator. If pX is a SELECT statement
2110 ** that can be simplified to a direct table access, then return
2111 ** a pointer to the SELECT statement. If pX is not a SELECT statement,
2112 ** or if the SELECT statement needs to be manifested into a transient
2113 ** table, then return NULL.
2114 */
2115 #ifndef SQLITE_OMIT_SUBQUERY
2130 }
2144 /* All SELECT results must be columns. */
2149 }
2151 }
2154 #ifndef SQLITE_OMIT_SUBQUERY
2155 /*
2156 ** Generate code that checks the left-most column of index table iCur to see if
2157 ** it contains any NULL entries. Cause the register at regHasNull to be set
2158 ** to a non-NULL value if iCur contains no NULLs. Cause register regHasNull
2159 ** to be set to NULL if iCur contains one or more NULL values.
2160 */
2169 }
2170 #endif
2173 #ifndef SQLITE_OMIT_SUBQUERY
2174 /*
2175 ** The argument is an IN operator with a list (not a subquery) on the
2176 ** right-hand side. Return TRUE if that list is constant.
2177 */
2187 }
2188 #endif
2190 /*
2191 ** This function is used by the implementation of the IN (...) operator.
2192 ** The pX parameter is the expression on the RHS of the IN operator, which
2193 ** might be either a list of expressions or a subquery.
2194 **
2195 ** The job of this routine is to find or create a b-tree object that can
2196 ** be used either to test for membership in the RHS set or to iterate through
2197 ** all members of the RHS set, skipping duplicates.
2198 **
2199 ** A cursor is opened on the b-tree object that is the RHS of the IN operator
2200 ** and pX->iTable is set to the index of that cursor.
2201 **
2202 ** The returned value of this function indicates the b-tree type, as follows:
2203 **
2204 ** IN_INDEX_ROWID - The cursor was opened on a database table.
2205 ** IN_INDEX_INDEX_ASC - The cursor was opened on an ascending index.
2206 ** IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
2207 ** IN_INDEX_EPH - The cursor was opened on a specially created and
2208 ** populated epheremal table.
2209 ** IN_INDEX_NOOP - No cursor was allocated. The IN operator must be
2210 ** implemented as a sequence of comparisons.
2211 **
2212 ** An existing b-tree might be used if the RHS expression pX is a simple
2213 ** subquery such as:
2214 **
2215 ** SELECT <column1>, <column2>... FROM <table>
2216 **
2217 ** If the RHS of the IN operator is a list or a more complex subquery, then
2218 ** an ephemeral table might need to be generated from the RHS and then
2219 ** pX->iTable made to point to the ephemeral table instead of an
2220 ** existing table.
2221 **
2222 ** The inFlags parameter must contain, at a minimum, one of the bits
2223 ** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP but not both. If inFlags contains
2224 ** IN_INDEX_MEMBERSHIP, then the generated table will be used for a fast
2225 ** membership test. When the IN_INDEX_LOOP bit is set, the IN index will
2226 ** be used to loop over all values of the RHS of the IN operator.
2227 **
2228 ** When IN_INDEX_LOOP is used (and the b-tree will be used to iterate
2229 ** through the set members) then the b-tree must not contain duplicates.
2230 ** An epheremal table will be created unless the selected columns are guaranteed
2231 ** to be unique - either because it is an INTEGER PRIMARY KEY or due to
2232 ** a UNIQUE constraint or index.
2233 **
2234 ** When IN_INDEX_MEMBERSHIP is used (and the b-tree will be used
2235 ** for fast set membership tests) then an epheremal table must
2236 ** be used unless <columns> is a single INTEGER PRIMARY KEY column or an
2237 ** index can be found with the specified <columns> as its left-most.
2238 **
2239 ** If the IN_INDEX_NOOP_OK and IN_INDEX_MEMBERSHIP are both set and
2240 ** if the RHS of the IN operator is a list (not a subquery) then this
2241 ** routine might decide that creating an ephemeral b-tree for membership
2242 ** testing is too expensive and return IN_INDEX_NOOP. In that case, the
2243 ** calling routine should implement the IN operator using a sequence
2244 ** of Eq or Ne comparison operations.
2245 **
2246 ** When the b-tree is being used for membership tests, the calling function
2247 ** might need to know whether or not the RHS side of the IN operator
2248 ** contains a NULL. If prRhsHasNull is not a NULL pointer and
2249 ** if there is any chance that the (...) might contain a NULL value at
2250 ** runtime, then a register is allocated and the register number written
2251 ** to *prRhsHasNull. If there is no chance that the (...) contains a
2252 ** NULL value, then *prRhsHasNull is left unchanged.
2253 **
2254 ** If a register is allocated and its location stored in *prRhsHasNull, then
2255 ** the value in that register will be NULL if the b-tree contains one or more
2256 ** NULL values, and it will be some non-NULL value if the b-tree contains no
2257 ** NULL values.
2258 **
2259 ** If the aiMap parameter is not NULL, it must point to an array containing
2260 ** one element for each column returned by the SELECT statement on the RHS
2261 ** of the IN(...) operator. The i'th entry of the array is populated with the
2262 ** offset of the index column that matches the i'th column returned by the
2263 ** SELECT. For example, if the expression and selected index are:
2264 **
2265 ** (?,?,?) IN (SELECT a, b, c FROM t1)
2266 ** CREATE INDEX i1 ON t1(b, c, a);
2267 **
2268 ** then aiMap[] is populated with {2, 0, 1}.
2269 */
2270 #ifndef SQLITE_OMIT_SUBQUERY
2277 ){
2287 /* If the RHS of this IN(...) operator is a SELECT, and if it matters
2288 ** whether or not the SELECT result contains NULL values, check whether
2289 ** or not NULL is actually possible (it may not be, for example, due
2290 ** to NOT NULL constraints in the schema). If no NULL values are possible,
2291 ** set prRhsHasNull to 0 before continuing. */
2297 }
2300 }
2301 }
2303 /* Check to see if an existing table or index can be used to
2304 ** satisfy the query. This is preferable to generating a new
2305 ** ephemeral table. */
2318 /* Code an OP_Transaction and OP_TableLock for <table>. */
2325 /* The "x IN (SELECT rowid FROM table)" case */
2338 /* Check that the affinity that will be used to perform each
2339 ** comparison is the same as the affinity of each column in table
2340 ** on the RHS of the IN operator. If it not, it is not possible to
2341 ** use any index of the RHS table. */
2353 /* sqlite3CompareAffinity() only returns TEXT if one side or the
2354 ** other has no affinity and the other side is TEXT. Hence,
2355 ** the only way for cmpaff to be TEXT is for idxaff to be TEXT
2356 ** and for the term on the LHS of the IN to have no affinity. */
2361 }
2362 }
2365 /* Search for an existing index that will work for this IN operator */
2370 /* Maximum nColumn is BMS-2, not BMS-1, so that we can compute
2371 ** BITMASK(nExpr) without overflowing */
2378 ){
2380 }
2381 }
2396 }
2398 }
2404 }
2408 /* If we reach this point, that means the index pIdx is usable */
2410 #ifndef SQLITE_OMIT_EXPLAIN
2413 P4_DYNAMIC);
2414 #endif
2422 #ifdef SQLITE_ENABLE_COLUMN_USED_MASK
2426 #endif
2430 }
2431 }
2433 }
2439 /* If no preexisting index is available for the IN clause
2440 ** and IN_INDEX_NOOP is an allowed reply
2441 ** and the RHS of the IN operator is a list, not a subquery
2442 ** and the RHS is not constant or has two or fewer terms,
2443 ** then it is not worth creating an ephemeral table to evaluate
2444 ** the IN operator so return IN_INDEX_NOOP.
2445 */
2450 ){
2452 }
2455 /* Could not find an existing table or index to use as the RHS b-tree.
2456 ** We will have to generate an ephemeral table to do the job.
2457 */
2465 }
2468 }
2473 }
2479 }
2481 }
2482 #endif
2484 #ifndef SQLITE_OMIT_SUBQUERY
2485 /*
2486 ** Argument pExpr is an (?, ?...) IN(...) expression. This
2487 ** function allocates and returns a nul-terminated string containing
2488 ** the affinities to be used for each column of the comparison.
2489 **
2490 ** It is the responsibility of the caller to ensure that the returned
2491 ** string is eventually freed using sqlite3DbFree().
2492 */
2510 }
2511 }
2513 }
2515 }
2516 #endif
2518 #ifndef SQLITE_OMIT_SUBQUERY
2519 /*
2520 ** Load the Parse object passed as the first argument with an error
2521 ** message of the form:
2522 **
2523 ** "sub-select returns N columns - expected M"
2524 */
2528 }
2529 #endif
2531 /*
2532 ** Expression pExpr is a vector that has been used in a context where
2533 ** it is not permitted. If pExpr is a sub-select vector, this routine
2534 ** loads the Parse object with a message of the form:
2535 **
2536 ** "sub-select returns N columns - expected 1"
2537 **
2538 ** Or, if it is a regular scalar vector:
2539 **
2540 ** "row value misused"
2541 */
2543 #ifndef SQLITE_OMIT_SUBQUERY
2547 #endif
2548 {
2550 }
2551 }
2553 /*
2554 ** Generate code for scalar subqueries used as a subquery expression, EXISTS,
2555 ** or IN operators. Examples:
2556 **
2557 ** (SELECT a FROM b) -- subquery
2558 ** EXISTS (SELECT a FROM b) -- EXISTS subquery
2559 ** x IN (4,5,11) -- IN operator with list on right-hand side
2560 ** x IN (SELECT a FROM b) -- IN operator with subquery on the right
2561 **
2562 ** The pExpr parameter describes the expression that contains the IN
2563 ** operator or subquery.
2564 **
2565 ** If parameter isRowid is non-zero, then expression pExpr is guaranteed
2566 ** to be of the form "<rowid> IN (?, ?, ?)", where <rowid> is a reference
2567 ** to some integer key column of a table B-Tree. In this case, use an
2568 ** intkey B-Tree to store the set of IN(...) values instead of the usual
2569 ** (slower) variable length keys B-Tree.
2570 **
2571 ** If rMayHaveNull is non-zero, that means that the operation is an IN
2572 ** (not a SELECT or EXISTS) and that the RHS might contains NULLs.
2573 ** All this routine does is initialize the register given by rMayHaveNull
2574 ** to NULL. Calling routines will take care of changing this register
2575 ** value to non-NULL if the RHS is NULL-free.
2576 **
2577 ** For a SELECT or EXISTS operator, return the register that holds the
2578 ** result. For a multi-column SELECT, the result is stored in a contiguous
2579 ** array of registers and the return value is the register of the left-most
2580 ** result column. Return 0 for IN operators or if an error occurs.
2581 */
2582 #ifndef SQLITE_OMIT_SUBQUERY
2588 ){
2595 /* The evaluation of the IN/EXISTS/SELECT must be repeated every time it
2596 ** is encountered if any of the following is true:
2597 **
2598 ** * The right-hand side is a correlated subquery
2599 ** * The right-hand side is an expression list containing variables
2600 ** * We are inside a trigger
2601 **
2602 ** If all of the above are false, then we can run this code just once
2603 ** save the results, and reuse the same result on subsequent invocations.
2604 */
2607 }
2609 #ifndef SQLITE_OMIT_EXPLAIN
2614 pParse->iNextSelectId
2615 );
2617 }
2618 #endif
2630 /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
2631 ** expression it is handled the same way. An ephemeral table is
2632 ** filled with index keys representing the results from the
2633 ** SELECT or the <exprlist>.
2634 **
2635 ** If the 'x' expression is a column value, or the SELECT...
2636 ** statement returns a column value, then the affinity of that
2637 ** column is used to build the index keys. If both 'x' and the
2638 ** SELECT... statement are columns, then numeric affinity is used
2639 ** if either column has NUMERIC or INTEGER affinity. If neither
2640 ** 'x' nor the SELECT... statement are columns, then numeric affinity
2641 ** is used.
2642 */
2649 /* Case 1: expr IN (SELECT ...)
2650 **
2651 ** Generate code to write the results of the select into the temporary
2652 ** table allocated and opened above.
2653 */
2658 /* If the LHS and RHS of the IN operator do not match, that
2659 ** error will have been caught long before we reach this point. */
2661 SelectDest dest;
2672 }
2682 );
2683 }
2684 }
2686 /* Case 2: expr IN (exprlist)
2687 **
2688 ** For each expression, build an index key from the evaluation and
2689 ** store it in the temporary table. If <expr> is a column, then use
2690 ** that columns affinity when building index keys. If <expr> is not
2691 ** a column, use numeric affinity.
2692 */
2702 }
2706 }
2708 /* Loop through each expression in <exprlist>. */
2716 /* If the expression is not constant then we will need to
2717 ** disable the test that was generated above that makes sure
2718 ** this code only executes once. Because for a non-constant
2719 ** expression we need to rerun this code each time.
2720 */
2724 }
2726 /* Evaluate the expression and insert it into the temp table */
2740 }
2741 }
2742 }
2745 }
2748 }
2750 }
2755 /* Case 3: (SELECT ... FROM ...)
2756 ** or: EXISTS(SELECT ... FROM ...)
2757 **
2758 ** For a SELECT, generate code to put the values for all columns of
2759 ** the first row into an array of registers and return the index of
2760 ** the first register.
2761 **
2762 ** If this is an EXISTS, write an integer 0 (not exists) or 1 (exists)
2763 ** into a register and return that register number.
2764 **
2765 ** In both cases, the query is augmented with "LIMIT 1". Any
2766 ** preexisting limit is discarded in place of the new LIMIT 1.
2767 */
2792 }
2799 }
2803 }
2807 }
2808 }
2812 }
2816 }
2820 }
2823 #ifndef SQLITE_OMIT_SUBQUERY
2824 /*
2825 ** Expr pIn is an IN(...) expression. This function checks that the
2826 ** sub-select on the RHS of the IN() operator has the same number of
2827 ** columns as the vector on the LHS. Or, if the RHS of the IN() is not
2828 ** a sub-query, that the LHS is a vector of size 1.
2829 */
2836 }
2840 }
2842 }
2843 #endif
2845 #ifndef SQLITE_OMIT_SUBQUERY
2846 /*
2847 ** Generate code for an IN expression.
2848 **
2849 ** x IN (SELECT ...)
2850 ** x IN (value, value, ...)
2851 **
2852 ** The left-hand side (LHS) is a scalar or vector expression. The
2853 ** right-hand side (RHS) is an array of zero or more scalar values, or a
2854 ** subquery. If the RHS is a subquery, the number of result columns must
2855 ** match the number of columns in the vector on the LHS. If the RHS is
2856 ** a list of values, the LHS must be a scalar.
2857 **
2858 ** The IN operator is true if the LHS value is contained within the RHS.
2859 ** The result is false if the LHS is definitely not in the RHS. The
2860 ** result is NULL if the presence of the LHS in the RHS cannot be
2861 ** determined due to NULLs.
2862 **
2863 ** This routine generates code that jumps to destIfFalse if the LHS is not
2864 ** contained within the RHS. If due to NULLs we cannot determine if the LHS
2865 ** is contained in the RHS then jump to destIfNull. If the LHS is contained
2866 ** within the RHS then fall through.
2867 **
2868 ** See the separate in-operator.md documentation file in the canonical
2869 ** SQLite source tree for additional information.
2870 */
2876 ){
2900 );
2903 /* Attempt to compute the RHS. After this step, if anything other than
2904 ** IN_INDEX_NOOP is returned, the table opened ith cursor pExpr->iTable
2905 ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
2906 ** the RHS has not yet been coded. */
2916 );
2917 #ifdef SQLITE_DEBUG
2918 /* Confirm that aiMap[] contains nVector integer values between 0 and
2919 ** nVector-1. */
2924 }
2925 #endif
2927 /* Code the LHS, the <expr> from "<expr> IN (...)". If the LHS is a
2928 ** vector, then it is stored in an array of nVector registers starting
2929 ** at r1.
2930 **
2931 ** sqlite3FindInIndex() might have reordered the fields of the LHS vector
2932 ** so that the fields are in the same order as an existing index. The
2933 ** aiMap[] array contains a mapping from the original LHS field order to
2934 ** the field order that matches the RHS index.
2935 */
2940 /* LHS fields are not reordered */
2943 /* Need to reorder the LHS fields according to aiMap */
2947 }
2948 }
2950 /* If sqlite3FindInIndex() did not find or create an index that is
2951 ** suitable for evaluating the IN operator, then evaluate using a
2952 ** sequence of comparisons.
2953 **
2954 ** This is step (1) in the in-operator.md optimized algorithm.
2955 */
2967 }
2972 }
2984 }
2986 }
2990 }
2994 }
2996 /* Step 2: Check to see if the LHS contains any NULL columns. If the
2997 ** LHS does contain NULLs then the result must be either FALSE or NULL.
2998 ** We will then skip the binary search of the RHS.
2999 */
3004 }
3010 }
3011 }
3013 /* Step 3. The LHS is now known to be non-NULL. Do the binary search
3014 ** of the RHS using the LHS as a probe. If found, the result is
3015 ** true.
3016 */
3018 /* In this case, the RHS is the ROWID of table b-tree and so we also
3019 ** know that the RHS is non-NULL. Hence, we combine steps 3 and 4
3020 ** into a single opcode. */
3027 /* Combine Step 3 and Step 5 into a single opcode */
3031 }
3032 /* Ordinary Step 3, for the case where FALSE and NULL are distinct */
3035 }
3037 /* Step 4. If the RHS is known to be non-NULL and we did not find
3038 ** an match on the search above, then the result must be FALSE.
3039 */
3043 }
3045 /* Step 5. If we do not care about the difference between NULL and
3046 ** FALSE, then just return false.
3047 */
3050 /* Step 6: Loop through rows of the RHS. Compare each row to the LHS.
3051 ** If any comparison is NULL, then the result is NULL. If all
3052 ** comparisons are FALSE then the final result is FALSE.
3053 **
3054 ** For a scalar LHS, it is sufficient to check just the first row
3055 ** of the RHS.
3056 */
3063 /* For nVector==1, combine steps 6 and 7 by immediately returning
3064 ** FALSE if the first comparison is not NULL */
3066 }
3078 }
3085 /* Step 7: If we reach this point, we know that the result must
3086 ** be false. */
3088 }
3090 /* Jumps here in order to return true. */
3093 sqlite3ExprCodeIN_finished:
3097 sqlite3ExprCodeIN_oom_error:
3100 }
3103 #ifndef SQLITE_OMIT_FLOATING_POINT
3104 /*
3105 ** Generate an instruction that will put the floating point
3106 ** value described by z[0..n-1] into register iMem.
3107 **
3108 ** The z[] string will probably not be zero-terminated. But the
3109 ** z[n] character is guaranteed to be something that does not look
3110 ** like the continuation of the number.
3111 */
3119 }
3120 }
3121 #endif
3124 /*
3125 ** Generate an instruction that will put the integer describe by
3126 ** text z[0..n-1] into register iMem.
3127 **
3128 ** Expr.u.zToken is always UTF8 and zero-terminated.
3129 */
3139 i64 value;
3144 #ifdef SQLITE_OMIT_FLOATING_POINT
3146 #else
3147 #ifndef SQLITE_OMIT_HEX_INTEGER
3151 #endif
3152 {
3154 }
3155 #endif
3159 }
3160 }
3161 }
3163 /*
3164 ** Erase column-cache entry number i
3165 */
3170 }
3171 }
3175 }
3176 }
3179 /*
3180 ** Record in the column cache that a particular column from a
3181 ** particular table is stored in a particular register.
3182 */
3189 /* Unless an error has occurred, register numbers are always positive. */
3193 /* The SQLITE_ColumnCache flag disables the column cache. This is used
3194 ** for testing only - to verify that SQLite always gets the same answer
3195 ** with and without the column cache.
3196 */
3199 /* First replace any existing entry.
3200 **
3201 ** Actually, the way the column cache is currently used, we are guaranteed
3202 ** that the object will never already be in cache. Verify this guarantee.
3203 */
3204 #ifndef NDEBUG
3207 }
3208 #endif
3210 /* If the cache is already full, delete the least recently used entry */
3218 }
3219 }
3223 }
3225 /* Add the new entry to the end of the cache */
3232 }
3234 /*
3235 ** Indicate that registers between iReg..iReg+nReg-1 are being overwritten.
3236 ** Purge the range of registers from the column cache.
3237 */
3245 i++;
3246 }
3247 }
3248 }
3250 /*
3251 ** Remember the current column cache context. Any new entries added
3252 ** added to the column cache after this call are removed when the
3253 ** corresponding pop occurs.
3254 */
3257 #ifdef SQLITE_DEBUG
3260 }
3261 #endif
3262 }
3264 /*
3265 ** Remove from the column cache any entries that were added since the
3266 ** the previous sqlite3ExprCachePush operation. In other words, restore
3267 ** the cache to the state it was in prior the most recent Push.
3268 */
3273 #ifdef SQLITE_DEBUG
3276 }
3277 #endif
3282 i++;
3283 }
3284 }
3285 }
3287 /*
3288 ** When a cached column is reused, make sure that its register is
3289 ** no longer available as a temp register. ticket #3879: that same
3290 ** register might be in the cache in multiple places, so be sure to
3291 ** get them all.
3292 */
3299 }
3300 }
3301 }
3303 /* Generate code that will load into register regOut a value that is
3304 ** appropriate for the iIdxCol-th column of index pIdx.
3305 */
3312 ){
3323 }
3324 }
3326 /*
3327 ** Generate code to extract the value of the iCol-th column of a table.
3328 */
3335 ){
3339 }
3347 }
3349 }
3352 }
3353 }
3355 /*
3356 ** Generate code that will extract the iColumn-th column from
3357 ** table pTab and store the column value in a register.
3358 **
3359 ** An effort is made to store the column value in register iReg. This
3360 ** is not garanteeed for GetColumn() - the result can be stored in
3361 ** any register. But the result is guaranteed to land in register iReg
3362 ** for GetColumnToReg().
3363 **
3364 ** There must be an open cursor to pTab in iTable when this routine
3365 ** is called. If iColumn<0 then code is generated that extracts the rowid.
3366 */
3373 u8 p5 /* P5 value for OP_Column + FLAGS */
3374 ){
3384 }
3385 }
3392 }
3394 }
3401 ){
3404 }
3407 /*
3408 ** Clear all column cache entries.
3409 */
3413 #ifdef SQLITE_DEBUG
3416 }
3417 #endif
3421 ){
3423 }
3424 }
3426 }
3428 /*
3429 ** Record the fact that an affinity change has occurred on iCount
3430 ** registers starting with iStart.
3431 */
3434 }
3436 /*
3437 ** Generate code to move content from registers iFrom...iFrom+nReg-1
3438 ** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
3439 */
3444 }
3446 #if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
3447 /*
3448 ** Return true if any register in the range iFrom..iTo (inclusive)
3449 ** is used as part of the column cache.
3450 **
3451 ** This routine is used within assert() and testcase() macros only
3452 ** and does not appear in a normal build.
3453 */
3460 }
3462 }
3466 /*
3467 ** Convert a scalar expression node to a TK_REGISTER referencing
3468 ** register iReg. The caller must ensure that iReg already contains
3469 ** the correct value for the expression.
3470 */
3476 }
3478 /*
3479 ** Evaluate an expression (either a vector or a scalar expression) and store
3480 ** the result in continguous temporary registers. Return the index of
3481 ** the first register used to store the result.
3482 **
3483 ** If the returned result register is a temporary scalar, then also write
3484 ** that register number into *piFreeable. If the returned result register
3485 ** is not a temporary or if the expression is a vector set *piFreeable
3486 ** to 0.
3487 */
3496 #if SQLITE_OMIT_SUBQUERY
3498 #else
3500 #endif
3507 }
3508 }
3509 }
3511 }
3514 /*
3515 ** Generate code into the current Vdbe to evaluate the given
3516 ** expression. Attempt to store the results in register "target".
3517 ** Return the register where results are stored.
3518 **
3519 ** With this routine, there is no guarantee that results will
3520 ** be stored in target. The result might be stored in some other
3521 ** register if it is convenient to do so. The calling function
3522 ** must check the return code and move the results to the desired
3523 ** register.
3524 */
3539 }
3545 }
3557 }
3558 /* Otherwise, fall thru into the TK_COLUMN case */
3559 }
3564 /* Generating CHECK constraints or inserting into partial index */
3567 /* Coding an expression that is part of an index where column names
3568 ** in the index refer to the table to which the index belongs */
3570 }
3571 }
3575 }
3579 }
3583 }
3584 #ifndef SQLITE_OMIT_FLOATING_POINT
3589 }
3590 #endif
3595 }
3599 }
3600 #ifndef SQLITE_OMIT_BLOB_LITERAL
3614 }
3615 #endif
3626 }
3628 }
3631 }
3632 #ifndef SQLITE_OMIT_CAST
3634 /* Expressions of the form: CAST(pLeft AS token) */
3639 }
3645 }
3651 /* fall-through */
3674 }
3676 }
3706 }
3713 #ifndef SQLITE_OMIT_FLOATING_POINT
3718 #endif
3727 }
3729 }
3738 }
3750 }
3765 }
3773 }
3775 }
3788 /* SQL functions can be expensive. So try to move constant functions
3789 ** out of the inner loop, even if that means an extra OP_Copy. */
3791 }
3797 }
3802 #ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
3805 }
3806 #endif
3810 }
3812 /* Attempt a direct implementation of the built-in COALESCE() and
3813 ** IFNULL() functions. This avoids unnecessary evaluation of
3814 ** arguments past the first non-NULL argument.
3815 */
3827 }
3830 }
3832 /* The UNLIKELY() function is a no-op. The result is the value
3833 ** of the first argument.
3834 */
3838 }
3840 #ifdef SQLITE_DEBUG
3841 /* The AFFINITY() function evaluates to a string that describes
3842 ** the type affinity of the argument. This is used for testing of
3843 ** the SQLite type logic.
3844 */
3853 }
3854 #endif
3860 }
3863 }
3864 }
3871 }
3873 /* For length() and typeof() functions with a column argument,
3874 ** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
3875 ** or OPFLAG_TYPEOFARG respectively, to avoid unnecessary data
3876 ** loading.
3877 */
3879 u8 exprOp;
3889 }
3890 }
3898 }
3899 #ifndef SQLITE_OMIT_VIRTUALTABLE
3900 /* Possibly overload the function if the first argument is
3901 ** a virtual table column.
3902 **
3903 ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
3904 ** second argument, not the first, as the argument to test to
3905 ** see if it is a column in a virtual table. This is done because
3906 ** the left operand of infix functions (the operand we want to
3907 ** control overloading) ends up as the second argument to the
3908 ** function. The expression "A glob B" is equivalent to
3909 ** "glob(B,A). We want to use the A in "A glob B" to test
3910 ** for function overloading. But we use the B term in "glob(B,A)".
3911 */
3916 }
3917 #endif
3921 }
3922 #ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
3929 }
3931 #endif
3932 {
3936 }
3939 }
3941 }
3942 #ifndef SQLITE_OMIT_SUBQUERY
3952 }
3954 }
3959 }
3963 ){
3966 }
3968 }
3979 }
3983 /*
3984 ** x BETWEEN y AND z
3985 **
3986 ** This is equivalent to
3987 **
3988 ** x>=y AND x<=z
3989 **
3990 ** X is stored in pExpr->pLeft.
3991 ** Y is stored in pExpr->pList->a[0].pExpr.
3992 ** Z is stored in pExpr->pList->a[1].pExpr.
3993 */
3997 }
4002 }
4005 /* If the opcode is TK_TRIGGER, then the expression is a reference
4006 ** to a column in the new.* or old.* pseudo-tables available to
4007 ** trigger programs. In this case Expr.iTable is set to 1 for the
4008 ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
4009 ** is set to the column of the pseudo-table to read, or to -1 to
4010 ** read the rowid field.
4011 **
4012 ** The expression is implemented using an OP_Param opcode. The p1
4013 ** parameter is set to 0 for an old.rowid reference, or to (i+1)
4014 ** to reference another column of the old.* pseudo-table, where
4015 ** i is the index of the column. For a new.rowid reference, p1 is
4016 ** set to (n+1), where n is the number of columns in each pseudo-table.
4017 ** For a reference to any other column in the new.* pseudo-table, p1
4018 ** is set to (n+2+i), where n and i are as defined previously. For
4019 ** example, if the table on which triggers are being fired is
4020 ** declared as:
4021 **
4022 ** CREATE TABLE t1(a, b);
4023 **
4024 ** Then p1 is interpreted as follows:
4025 **
4026 ** p1==0 -> old.rowid p1==3 -> new.rowid
4027 ** p1==1 -> old.a p1==4 -> new.a
4028 ** p1==2 -> old.b p1==5 -> new.b
4029 */
4042 target
4043 ));
4045 #ifndef SQLITE_OMIT_FLOATING_POINT
4046 /* If the column has REAL affinity, it may currently be stored as an
4047 ** integer. Use OP_RealAffinity to make sure it is really real.
4048 **
4049 ** EVIDENCE-OF: R-60985-57662 SQLite will convert the value back to
4050 ** floating point when extracting it from the record. */
4053 ){
4055 }
4056 #endif
4058 }
4063 }
4074 }
4076 /*
4077 ** Form A:
4078 ** CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
4079 **
4080 ** Form B:
4081 ** CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
4082 **
4083 ** Form A is can be transformed into the equivalent form B as follows:
4084 ** CASE WHEN x=e1 THEN r1 WHEN x=e2 THEN r2 ...
4085 ** WHEN x=eN THEN rN ELSE y END
4086 **
4087 ** X (if it exists) is in pExpr->pLeft.
4088 ** Y is in the last element of pExpr->x.pList if pExpr->x.pList->nExpr is
4089 ** odd. The Y is also optional. If the number of elements in x.pList
4090 ** is even, then Y is omitted and the "otherwise" result is NULL.
4091 ** Ei is in pExpr->pList->a[i*2] and Ri is pExpr->pList->a[i*2+1].
4092 **
4093 ** The result of the expression is the Ri for the first matching Ei,
4094 ** or if there is no matching Ei, the ELSE term Y, or if there is
4095 ** no ELSE term, NULL.
4096 */
4124 /* Ticket b351d95f9cd5ef17e9d9dbae18f5ca8611190001:
4125 ** The value in regFree1 might get SCopy-ed into the file result.
4126 ** So make sure that the regFree1 register is not reused for other
4127 ** purposes and possibly overwritten. */
4129 }
4137 }
4146 }
4153 }
4158 }
4159 #ifndef SQLITE_OMIT_TRIGGER
4165 );
4170 }
4173 }
4182 }
4185 }
4186 #endif
4187 }
4191 }
4193 /*
4194 ** Factor out the code of the given expression to initialization time.
4195 **
4196 ** If regDest>=0 then the result is always stored in that register and the
4197 ** result is not reusable. If regDest<0 then this routine is free to
4198 ** store the value whereever it wants. The register where the expression
4199 ** is stored is returned. When regDest<0, two identical expressions will
4200 ** code to the same register.
4201 */
4206 ){
4216 }
4217 }
4218 }
4226 }
4229 }
4231 /*
4232 ** Generate code to evaluate an expression and store the results
4233 ** into a register. Return the register number where the results
4234 ** are stored.
4235 **
4236 ** If the register is a temporary register that can be deallocated,
4237 ** then write its number into *pReg. If the result register is not
4238 ** a temporary, then set *pReg to zero.
4239 **
4240 ** If pExpr is a constant, then this routine might generate this
4241 ** code to fill the register in the initialization section of the
4242 ** VDBE program, in order to factor it out of the evaluation loop.
4243 */
4250 ){
4261 }
4262 }
4264 }
4266 /*
4267 ** Generate code that will evaluate expression pExpr and store the
4268 ** results in register target. The results are guaranteed to appear
4269 ** in register target.
4270 */
4282 }
4283 }
4284 }
4286 /*
4287 ** Make a transient copy of expression pExpr and then code it using
4288 ** sqlite3ExprCode(). This routine works just like sqlite3ExprCode()
4289 ** except that the input expression is guaranteed to be unchanged.
4290 */
4296 }
4298 /*
4299 ** Generate code that will evaluate expression pExpr and store the
4300 ** results in register target. The results are guaranteed to appear
4301 ** in register target. If the expression is constant, then this routine
4302 ** might choose to code the expression at initialization time.
4303 */
4309 }
4310 }
4312 /*
4313 ** Generate code that evaluates the given expression and puts the result
4314 ** in register target.
4315 **
4316 ** Also make a copy of the expression results into another "cache" register
4317 ** and modify the expression so that the next time it is evaluated,
4318 ** the result is a copy of the cache register.
4319 **
4320 ** This routine is used for expressions that are used multiple
4321 ** times. They are evaluated once and the results of the expression
4322 ** are reused.
4323 */
4334 }
4336 /*
4337 ** Generate code that pushes the value of every element of the given
4338 ** expression list into a sequence of registers beginning at target.
4339 **
4340 ** Return the number of elements evaluated. The number returned will
4341 ** usually be pList->nExpr but might be reduced if SQLITE_ECEL_OMITREF
4342 ** is defined.
4343 **
4344 ** The SQLITE_ECEL_DUP flag prevents the arguments from being
4345 ** filled using OP_SCopy. OP_Copy must be used instead.
4346 **
4347 ** The SQLITE_ECEL_FACTOR argument allows constant arguments to be
4348 ** factored out into initialization code.
4349 **
4350 ** The SQLITE_ECEL_REF flag means that expressions in the list with
4351 ** ExprList.a[].u.x.iOrderByCol>0 have already been evaluated and stored
4352 ** in registers at srcReg, and so the value can be copied from there.
4353 ** If SQLITE_ECEL_OMITREF is also set, then the values with u.x.iOrderByCol>0
4354 ** are simply omitted rather than being copied from srcReg.
4355 */
4361 u8 flags /* SQLITE_ECEL_* flags */
4362 ){
4376 i--;
4377 n--;
4380 }
4391 ){
4395 }
4396 }
4397 }
4398 }
4400 }
4402 /*
4403 ** Generate code for a BETWEEN operator.
4404 **
4405 ** x BETWEEN y AND z
4406 **
4407 ** The above is equivalent to
4408 **
4409 ** x>=y AND x<=z
4410 **
4411 ** Code it as such, taking care to do the common subexpression
4412 ** elimination of x.
4413 **
4414 ** The xJumpIf parameter determines details:
4415 **
4416 ** NULL: Store the boolean result in reg[dest]
4417 ** sqlite3ExprIfTrue: Jump to dest if true
4418 ** sqlite3ExprIfFalse: Jump to dest if false
4419 **
4420 ** The jumpIfNull parameter is ignored if xJumpIf is NULL.
4421 */
4428 ){
4455 /* Mark the expression is being from the ON or USING clause of a join
4456 ** so that the sqlite3ExprCodeTarget() routine will not attempt to move
4457 ** it into the Parse.pConstExpr list. We should use a new bit for this,
4458 ** for clarity, but we are out of bits in the Expr.flags field so we
4459 ** have to reuse the EP_FromJoin bit. Bummer. */
4462 }
4465 /* Ensure adequate test coverage */
4475 }
4477 /*
4478 ** Generate code for a boolean expression such that a jump is made
4479 ** to the label "dest" if the expression is true but execution
4480 ** continues straight thru if the expression is false.
4481 **
4482 ** If the expression evaluates to NULL (neither true nor false), then
4483 ** take the jump if the jumpIfNull flag is SQLITE_JUMPIFNULL.
4484 **
4485 ** This code depends on the fact that certain token values (ex: TK_EQ)
4486 ** are the same as opcode values (ex: OP_Eq) that implement the corresponding
4487 ** operation. Special comments in vdbe.c and the mkopcodeh.awk script in
4488 ** the make process cause these values to align. Assert()s in the code
4489 ** below verify that the numbers are aligned correctly.
4490 */
4512 }
4520 }
4525 }
4540 }
4542 }
4549 /* Fall thru */
4575 }
4586 }
4591 }
4592 #ifndef SQLITE_OMIT_SUBQUERY
4600 }
4601 #endif
4603 default_expr:
4607 /* No-op */
4614 }
4616 }
4617 }
4620 }
4622 /*
4623 ** Generate code for a boolean expression such that a jump is made
4624 ** to the label "dest" if the expression is false but execution
4625 ** continues straight thru if the expression is true.
4626 **
4627 ** If the expression evaluates to NULL (neither true nor false) then
4628 ** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
4629 ** is 0.
4630 */
4642 /* The value of pExpr->op and op are related as follows:
4643 **
4644 ** pExpr->op op
4645 ** --------- ----------
4646 ** TK_ISNULL OP_NotNull
4647 ** TK_NOTNULL OP_IsNull
4648 ** TK_NE OP_Eq
4649 ** TK_EQ OP_Ne
4650 ** TK_GT OP_Le
4651 ** TK_LE OP_Gt
4652 ** TK_GE OP_Lt
4653 ** TK_LT OP_Ge
4654 **
4655 ** For other values of pExpr->op, op is undefined and unused.
4656 ** The value of TK_ and OP_ constants are arranged such that we
4657 ** can compute the mapping above using the following expression.
4658 ** Assert()s verify that the computation is correct.
4659 */
4662 /* Verify correct alignment of TK_ and OP_ constants
4663 */
4681 }
4691 }
4696 }
4706 /* IS TRUE and IS NOT FALSE */
4711 /* IS FALSE and IS NOT TRUE */
4714 }
4716 }
4723 /* Fall thru */
4749 }
4758 }
4763 }
4764 #ifndef SQLITE_OMIT_SUBQUERY
4772 }
4774 }
4775 #endif
4777 default_expr:
4781 /* no-op */
4788 }
4790 }
4791 }
4794 }
4796 /*
4797 ** Like sqlite3ExprIfFalse() except that a copy is made of pExpr before
4798 ** code generation, and that copy is deleted after code generation. This
4799 ** ensures that the original pExpr is unchanged.
4800 */
4806 }
4808 }
4810 /*
4811 ** Expression pVar is guaranteed to be an SQL variable. pExpr may be any
4812 ** type of expression.
4813 **
4814 ** If pExpr is a simple SQL value - an integer, real, string, blob
4815 ** or NULL value - then the VDBE currently being prepared is configured
4816 ** to re-prepare each time a new value is bound to variable pVar.
4817 **
4818 ** Additionally, if pExpr is a simple SQL value and the value is the
4819 ** same as that currently bound to variable pVar, non-zero is returned.
4820 ** Otherwise, if the values are not the same or if pExpr is not a simple
4821 ** SQL value, zero is returned.
4822 */
4836 }
4838 }
4841 }
4844 }
4846 /*
4847 ** Do a deep comparison of two expression trees. Return 0 if the two
4848 ** expressions are completely identical. Return 1 if they differ only
4849 ** by a COLLATE operator at the top level. Return 2 if there are differences
4850 ** other than the top-level COLLATE operator.
4851 **
4852 ** If any subelement of pB has Expr.iTable==(-1) then it is allowed
4853 ** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
4854 **
4855 ** The pA side might be using TK_REGISTER. If that is the case and pB is
4856 ** not using TK_REGISTER but is otherwise equivalent, then still return 0.
4857 **
4858 ** Sometimes this routine will return 2 even if the two expressions
4859 ** really are equivalent. If we cannot prove that the expressions are
4860 ** identical, we return 2 just to be safe. So if this routine
4861 ** returns 2, then you do not really know for certain if the two
4862 ** expressions are the same. But if you get a 0 or 1 return, then you
4863 ** can be sure the expressions are the same. In the places where
4864 ** this routine is used, it does not hurt to get an extra 2 - that
4865 ** just might result in some slightly slower code. But returning
4866 ** an incorrect 0 or 1 could lead to a malfunction.
4867 **
4868 ** If pParse is not NULL then TK_VARIABLE terms in pA with bindings in
4869 ** pParse->pReprepare can be matched against literals in pB. The
4870 ** pParse->pVdbe->expmask bitmask is updated for each variable referenced.
4871 ** If pParse is NULL (the normal case) then any TK_VARIABLE term in
4872 ** Argument pParse should normally be NULL. If it is not NULL and pA or
4873 ** pB causes a return value of 2.
4874 */
4876 u32 combinedFlags;
4879 }
4882 }
4887 }
4889 }
4893 }
4896 }
4898 }
4904 }
4905 }
4916 }
4917 }
4919 }
4921 /*
4922 ** Compare two ExprList objects. Return 0 if they are identical and
4923 ** non-zero if they differ in any way.
4924 **
4925 ** If any subelement of pB has Expr.iTable==(-1) then it is allowed
4926 ** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
4927 **
4928 ** This routine might return non-zero for equivalent ExprLists. The
4929 ** only consequence will be disabled optimizations. But this routine
4930 ** must never return 0 if the two ExprList objects are different, or
4931 ** a malfunction will result.
4932 **
4933 ** Two NULL pointers are considered to be the same. But a NULL pointer
4934 ** always differs from a non-NULL pointer.
4935 */
4946 }
4948 }
4950 /*
4951 ** Like sqlite3ExprCompare() except COLLATE operators at the top-level
4952 ** are ignored.
4953 */
4958 iTab);
4959 }
4961 /*
4962 ** Return true if we can prove the pE2 will always be true if pE1 is
4963 ** true. Return false if we cannot complete the proof or if pE2 might
4964 ** be false. Examples:
4965 **
4966 ** pE1: x==5 pE2: x==5 Result: true
4967 ** pE1: x>0 pE2: x==5 Result: false
4968 ** pE1: x=21 pE2: x=21 OR y=43 Result: true
4969 ** pE1: x!=123 pE2: x IS NOT NULL Result: true
4970 ** pE1: x!=?1 pE2: x IS NOT NULL Result: true
4971 ** pE1: x IS NULL pE2: x IS NOT NULL Result: false
4972 ** pE1: x IS ?2 pE2: x IS NOT NULL Reuslt: false
4973 **
4974 ** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
4975 ** Expr.iTable<0 then assume a table number given by iTab.
4976 **
4977 ** If pParse is not NULL, then the values of bound variables in pE1 are
4978 ** compared against literal values in pE2 and pParse->pVdbe->expmask is
4979 ** modified to record which bound variables are referenced. If pParse
4980 ** is NULL, then false will be returned if pE1 contains any bound variables.
4981 **
4982 ** When in doubt, return false. Returning true might give a performance
4983 ** improvement. Returning false might cause a performance reduction, but
4984 ** it will always give the correct answer and is hence always safe.
4985 */
4989 }
4993 ){
4995 }
5000 }
5002 }
5004 /*
5005 ** This is the Expr node callback for sqlite3ExprImpliesNotNullRow().
5006 ** If the expression node requires that the table at pWalker->iCur
5007 ** have a non-NULL column, then set pWalker->eCode to 1 and abort.
5008 */
5010 /* This routine is only called for WHERE clause expressions and so it
5011 ** cannot have any TK_AGG_COLUMN entries because those are only found
5012 ** in HAVING clauses. We can get a TK_AGG_FUNCTION in a WHERE clause,
5013 ** but that is an illegal construct and the query will be rejected at
5014 ** a later stage of processing, so the TK_AGG_FUNCTION case does not
5015 ** need to be considered here. */
5038 }
5042 }
5043 }
5045 /*
5046 ** Return true (non-zero) if expression p can only be true if at least
5047 ** one column of table iTab is non-null. In other words, return true
5048 ** if expression p will always be NULL or false if every column of iTab
5049 ** is NULL.
5050 **
5051 ** False negatives are acceptable. In other words, it is ok to return
5052 ** zero even if expression p will never be true of every column of iTab
5053 ** is NULL. A false negative is merely a missed optimization opportunity.
5054 **
5055 ** False positives are not allowed, however. A false positive may result
5056 ** in an incorrect answer.
5057 **
5058 ** Terms of p that are marked with EP_FromJoin (and hence that come from
5059 ** the ON or USING clauses of LEFT JOINS) are excluded from the analysis.
5060 **
5061 ** This routine is used to check if a LEFT JOIN can be converted into
5062 ** an ordinary JOIN. The p argument is the WHERE clause. If the WHERE
5063 ** clause requires that some column of the right table of the LEFT JOIN
5064 ** be non-NULL, then the LEFT JOIN can be safely converted into an
5065 ** ordinary join.
5066 */
5068 Walker w;
5076 }
5078 /*
5079 ** An instance of the following structure is used by the tree walker
5080 ** to determine if an expression can be evaluated by reference to the
5081 ** index only, without having to do a search for the corresponding
5082 ** table entry. The IdxCover.pIdx field is the index. IdxCover.iCur
5083 ** is the cursor for the table.
5084 */
5088 };
5090 /*
5091 ** Check to see if there are references to columns in table
5092 ** pWalker->u.pIdxCover->iCur can be satisfied using the index
5093 ** pWalker->u.pIdxCover->pIdx.
5094 */
5099 ){
5102 }
5104 }
5106 /*
5107 ** Determine if an index pIdx on table with cursor iCur contains will
5108 ** the expression pExpr. Return true if the index does cover the
5109 ** expression and false if the pExpr expression references table columns
5110 ** that are not found in the index pIdx.
5111 **
5112 ** An index covering an expression means that the expression can be
5113 ** evaluated using only the index and without having to lookup the
5114 ** corresponding table entry.
5115 */
5120 ){
5121 Walker w;
5130 }
5133 /*
5134 ** An instance of the following structure is used by the tree walker
5135 ** to count references to table columns in the arguments of an
5136 ** aggregate function, in order to implement the
5137 ** sqlite3FunctionThisSrc() routine.
5138 */
5143 };
5145 /*
5146 ** Count the number of references to columns.
5147 */
5149 /* The NEVER() on the second term is because sqlite3FunctionUsesThisSrc()
5150 ** is always called before sqlite3ExprAnalyzeAggregates() and so the
5151 ** TK_COLUMNs have not yet been converted into TK_AGG_COLUMN. If
5152 ** sqlite3FunctionUsesThisSrc() is used differently in the future, the
5153 ** NEVER() will need to be removed. */
5161 }
5166 }
5167 }
5169 }
5171 /*
5172 ** Determine if any of the arguments to the pExpr Function reference
5173 ** pSrcList. Return true if they do. Also return true if the function
5174 ** has no arguments or has only constant arguments. Return false if pExpr
5175 ** references columns but not columns of tables found in pSrcList.
5176 */
5178 Walker w;
5189 }
5191 /*
5192 ** Add a new element to the pAggInfo->aCol[] array. Return the index of
5193 ** the new element. Return a negative number if malloc fails.
5194 */
5198 db,
5202 &i
5203 );
5205 }
5207 /*
5208 ** Add a new element to the pAggInfo->aFunc[] array. Return the index of
5209 ** the new element. Return a negative number if malloc fails.
5210 */
5214 db,
5218 &i
5219 );
5221 }
5223 /*
5224 ** This is the xExprCallback for a tree walker. It is used to
5225 ** implement sqlite3ExprAnalyzeAggregates(). See sqlite3ExprAnalyzeAggregates
5226 ** for additional information.
5227 */
5240 /* Check to see if the column is in one of the tables in the FROM
5241 ** clause of the aggregate query */
5248 /* If we reach this point, it means that pExpr refers to a table
5249 ** that is in the FROM clause of the aggregate query.
5250 **
5251 ** Make an entry for the column in pAggInfo->aCol[] if there
5252 ** is not an entry there already.
5253 */
5260 }
5261 }
5264 ){
5283 }
5284 }
5285 }
5288 }
5289 }
5290 /* There is now an entry for pExpr in pAggInfo->aCol[] (either
5291 ** because it was there before or because we just created it).
5292 ** Convert the pExpr to be a TK_AGG_COLUMN referring to that
5293 ** pAggInfo->aCol[] entry.
5294 */
5302 }
5304 }
5308 ){
5309 /* Check to see if pExpr is a duplicate of another aggregate
5310 ** function that is already in the pAggInfo structure
5311 */
5316 }
5317 }
5319 /* pExpr is original. Make a new entry in pAggInfo->aFunc[]
5320 */
5336 }
5337 }
5338 }
5339 /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
5340 */
5348 }
5349 }
5350 }
5352 }
5357 }
5361 }
5363 /*
5364 ** Analyze the pExpr expression looking for aggregate functions and
5365 ** for variables that need to be added to AggInfo object that pNC->pAggInfo
5366 ** points to. Additional entries are made on the AggInfo object as
5367 ** necessary.
5368 **
5369 ** This routine should only be called after the expression has been
5370 ** analyzed by sqlite3ResolveExprNames().
5371 */
5373 Walker w;
5381 }
5383 /*
5384 ** Call sqlite3ExprAnalyzeAggregates() for every expression in an
5385 ** expression list. Return the number of errors.
5386 **
5387 ** If an error is found, the analysis is cut short.
5388 */
5395 }
5396 }
5397 }
5399 /*
5400 ** Allocate a single new register for use to hold some intermediate result.
5401 */
5405 }
5407 }
5409 /*
5410 ** Deallocate a register, making available for reuse for some other
5411 ** purpose.
5412 **
5413 ** If a register is currently being used by the column cache, then
5414 ** the deallocation is deferred until the column cache line that uses
5415 ** the register becomes stale.
5416 */
5425 }
5426 }
5428 }
5429 }
5431 /*
5432 ** Allocate or deallocate a block of nReg consecutive registers.
5433 */
5446 }
5448 }
5453 }
5458 }
5459 }
5461 /*
5462 ** Mark all temporary registers as being unavailable for reuse.
5463 */
5467 }
5469 /*
5470 ** Validate that no temporary register falls within the range of
5471 ** iFirst..iLast, inclusive. This routine is only call from within assert()
5472 ** statements.
5473 */
5474 #ifdef SQLITE_DEBUG
5480 ){
5482 }
5486 }
5487 }
5489 }