| blob | 8282c99a4abb522a80286d6a6948243a02098636 |
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 }
671 }
672 }
674 /*
675 ** Set the Expr.nHeight variable in the structure passed as an
676 ** argument. An expression with no children, Expr.pList or
677 ** Expr.pSelect member has a height of 1. Any other expression
678 ** has a height equal to the maximum height of any other
679 ** referenced Expr plus one.
680 **
681 ** Also propagate EP_Propagate flags up from Expr.x.pList to Expr.flags,
682 ** if appropriate.
683 */
693 }
695 }
697 /*
698 ** Set the Expr.nHeight variable using the exprSetHeight() function. If
699 ** the height is greater than the maximum allowed expression depth,
700 ** leave an error in pParse.
701 **
702 ** Also propagate all EP_Propagate flags from the Expr.x.pList into
703 ** Expr.flags.
704 */
709 }
711 /*
712 ** Return the maximum height of any expression tree referenced
713 ** by the select statement passed as an argument.
714 */
719 }
721 /*
722 ** Propagate all EP_Propagate flags from the Expr.x.pList into
723 ** Expr.flags.
724 */
728 }
729 }
730 #define exprSetHeight(y)
733 /*
734 ** This routine is the core allocator for Expr nodes.
735 **
736 ** Construct a new expression node and return a pointer to it. Memory
737 ** for this node and for the pToken argument is a single allocation
738 ** obtained from sqlite3DbMalloc(). The calling function
739 ** is responsible for making sure the node eventually gets freed.
740 **
741 ** If dequote is true, then the token (if it exists) is dequoted.
742 ** If dequote is false, no dequoting is performed. The deQuote
743 ** parameter is ignored if pToken is NULL or if the token does not
744 ** appear to be quoted. If the quotes were of the form "..." (double-quotes)
745 ** then the EP_DblQuoted flag is set on the expression node.
746 **
747 ** Special case: If op==TK_INTEGER and pToken points to a string that
748 ** can be translated into a 32-bit integer, then the token is not
749 ** stored in u.zToken. Instead, the integer values is written
750 ** into u.iValue and the EP_IntValue flag is set. No extra storage
751 ** is allocated to hold the integer text and the dequote flag is ignored.
752 */
758 ){
769 }
770 }
788 }
789 }
790 }
791 #if SQLITE_MAX_EXPR_DEPTH>0
793 #endif
794 }
796 }
798 /*
799 ** Allocate a new expression node from a zero-terminated token that has
800 ** already been dequoted.
801 */
806 ){
807 Token x;
811 }
813 /*
814 ** Attach subtrees pLeft and pRight to the Expr node pRoot.
815 **
816 ** If pRoot==NULL that means that a memory allocation error has occurred.
817 ** In that case, delete the subtrees pLeft and pRight.
818 */
823 Expr *pRight
824 ){
833 }
837 }
839 }
840 }
842 /*
843 ** Allocate an Expr node which joins as many as two subtrees.
844 **
845 ** One or both of the subtrees can be NULL. Return a pointer to the new
846 ** Expr node. Or, if an OOM error occurs, set pParse->db->mallocFailed,
847 ** free the subtrees and return NULL.
848 */
854 ){
857 /* Take advantage of short-circuit false optimization for AND */
865 }
867 }
870 }
872 }
874 /*
875 ** Add pSelect to the Expr.x.pSelect field. Or, if pExpr is NULL (due
876 ** do a memory allocation failure) then delete the pSelect object.
877 */
886 }
887 }
890 /*
891 ** If the expression is always either TRUE or FALSE (respectively),
892 ** then return 1. If one cannot determine the truth value of the
893 ** expression at compile-time return 0.
894 **
895 ** This is an optimization. If is OK to return 0 here even if
896 ** the expression really is always false or false (a false negative).
897 ** But it is a bug to return 1 if the expression might have different
898 ** boolean values in different circumstances (a false positive.)
899 **
900 ** Note that if the expression is part of conditional for a
901 ** LEFT JOIN, then we cannot determine at compile-time whether or not
902 ** is it true or false, so always return 0.
903 */
909 }
915 }
917 /*
918 ** Join two expressions using an AND operator. If either expression is
919 ** NULL, then just return the other expression.
920 **
921 ** If one side or the other of the AND is known to be false, then instead
922 ** of returning an AND expression, just return a constant expression with
923 ** a value of false.
924 */
938 }
939 }
941 /*
942 ** Construct a new expression node for a function with multiple
943 ** arguments.
944 */
953 }
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 }
1476 }
1479 }
1480 #else
1484 }
1485 #endif
1488 /*
1489 ** Add a new element to the end of an expression list. If pList is
1490 ** initially NULL, then create a new expression list.
1491 **
1492 ** The pList argument must be either NULL or a pointer to an ExprList
1493 ** obtained from a prior call to sqlite3ExprListAppend(). This routine
1494 ** may not be used with an ExprList obtained from sqlite3ExprListDup().
1495 ** Reason: This routine assumes that the number of slots in pList->a[]
1496 ** is a power of two. That is true for sqlite3ExprListAppend() returns
1497 ** but is not necessarily true from the return value of sqlite3ExprListDup().
1498 **
1499 ** If a memory allocation error occurs, the entire list is freed and
1500 ** NULL is returned. If non-NULL is returned, then it is guaranteed
1501 ** that the new entry was successfully appended.
1502 */
1507 ){
1515 }
1523 }
1525 }
1533 no_mem:
1534 /* Avoid leaking memory if malloc has failed. */
1538 }
1540 /*
1541 ** pColumns and pExpr form a vector assignment which is part of the SET
1542 ** clause of an UPDATE statement. Like this:
1543 **
1544 ** (a,b,c) = (expr1,expr2,expr3)
1545 ** Or: (a,b,c) = (SELECT x,y,z FROM ....)
1546 **
1547 ** For each term of the vector assignment, append new entries to the
1548 ** expression list pList. In the case of a subquery on the RHS, append
1549 ** TK_SELECT_COLUMN expressions.
1550 */
1556 ){
1561 /* pColumns can only be NULL due to an OOM but an OOM will cause an
1562 ** exit prior to this routine being invoked */
1566 /* If the RHS is a vector, then we can immediately check to see that
1567 ** the size of the RHS and LHS match. But if the RHS is a SELECT,
1568 ** wildcards ("*") in the result set of the SELECT must be expanded before
1569 ** we can do the size check, so defer the size check until code generation.
1570 */
1575 }
1584 }
1585 }
1592 /* Store the SELECT statement in pRight so it will be deleted when
1593 ** sqlite3ExprListDelete() is called */
1597 /* Remember the size of the LHS in iTable so that we can check that
1598 ** the RHS and LHS sizes match during code generation. */
1600 }
1602 vector_append_error:
1606 }
1608 /*
1609 ** Set the sort order for the last element on the given ExprList.
1610 */
1618 }
1620 }
1622 /*
1623 ** Set the ExprList.a[].zName element of the most recently added item
1624 ** on the expression list.
1625 **
1626 ** pList might be NULL following an OOM error. But pName should never be
1627 ** NULL. If a memory allocation fails, the pParse->db->mallocFailed flag
1628 ** is set.
1629 */
1635 ){
1644 }
1645 }
1647 /*
1648 ** Set the ExprList.a[].zSpan element of the most recently added item
1649 ** on the expression list.
1650 **
1651 ** pList might be NULL following an OOM error. But pSpan should never be
1652 ** NULL. If a memory allocation fails, the pParse->db->mallocFailed flag
1653 ** is set.
1654 */
1659 ){
1669 }
1670 }
1672 /*
1673 ** If the expression list pEList contains more than iLimit elements,
1674 ** leave an error message in pParse.
1675 */
1680 ){
1686 }
1687 }
1689 /*
1690 ** Delete an entire expression list.
1691 */
1700 pItem++;
1703 }
1706 }
1708 /*
1709 ** Return the bitwise-OR of all Expr.flags fields in the given
1710 ** ExprList.
1711 */
1720 }
1721 }
1723 }
1725 /*
1726 ** This is a SELECT-node callback for the expression walker that
1727 ** always "fails". By "fail" in this case, we mean set
1728 ** pWalker->eCode to zero and abort.
1729 **
1730 ** This callback is used by multiple expression walkers.
1731 */
1736 }
1738 /*
1739 ** These routines are Walker callbacks used to check expressions to
1740 ** see if they are "constant" for some definition of constant. The
1741 ** Walker.eCode value determines the type of "constant" we are looking
1742 ** for.
1743 **
1744 ** These callback routines are used to implement the following:
1745 **
1746 ** sqlite3ExprIsConstant() pWalker->eCode==1
1747 ** sqlite3ExprIsConstantNotJoin() pWalker->eCode==2
1748 ** sqlite3ExprIsTableConstant() pWalker->eCode==3
1749 ** sqlite3ExprIsConstantOrFunction() pWalker->eCode==4 or 5
1750 **
1751 ** In all cases, the callbacks set Walker.eCode=0 and abort if the expression
1752 ** is found to not be a constant.
1753 **
1754 ** The sqlite3ExprIsConstantOrFunction() is used for evaluating expressions
1755 ** in a CREATE TABLE statement. The Walker.eCode value is 5 when parsing
1756 ** an existing schema and 4 when processing a new statement. A bound
1757 ** parameter raises an error for new statements, but is silently converted
1758 ** to NULL for existing schemas. This allows sqlite_master tables that
1759 ** contain a bound parameter because they were generated by older versions
1760 ** of SQLite to be parsed by newer versions of SQLite without raising a
1761 ** malformed schema error.
1762 */
1765 /* If pWalker->eCode is 2 then any term of the expression that comes from
1766 ** the ON or USING clauses of a left join disqualifies the expression
1767 ** from being considered constant. */
1771 }
1774 /* Consider functions to be constant if all their arguments are constant
1775 ** and either pWalker->eCode==4 or 5 or the function has the
1776 ** SQLITE_FUNC_CONST flag. */
1783 }
1794 }
1795 /* Fall through */
1802 /* Silently convert bound parameters that appear inside of CREATE
1803 ** statements into a NULL when parsing the CREATE statement text out
1804 ** of the sqlite_master table */
1807 /* A bound parameter in a CREATE statement that originates from
1808 ** sqlite3_prepare() causes an error */
1811 }
1812 /* Fall through */
1817 }
1818 }
1820 Walker w;
1824 #ifdef SQLITE_DEBUG
1826 #endif
1830 }
1832 /*
1833 ** Walk an expression tree. Return non-zero if the expression is constant
1834 ** and 0 if it involves variables or function calls.
1835 **
1836 ** For the purposes of this function, a double-quoted string (ex: "abc")
1837 ** is considered a variable but a single-quoted string (ex: 'abc') is
1838 ** a constant.
1839 */
1842 }
1844 /*
1845 ** Walk an expression tree. Return non-zero if the expression is constant
1846 ** that does no originate from the ON or USING clauses of a join.
1847 ** Return 0 if it involves variables or function calls or terms from
1848 ** an ON or USING clause.
1849 */
1852 }
1854 /*
1855 ** Walk an expression tree. Return non-zero if the expression is constant
1856 ** for any single row of the table with cursor iCur. In other words, the
1857 ** expression must not refer to any non-deterministic function nor any
1858 ** table other than iCur.
1859 */
1862 }
1865 /*
1866 ** sqlite3WalkExpr() callback used by sqlite3ExprIsConstantOrGroupBy().
1867 */
1872 /* Check if pExpr is identical to any GROUP BY term. If so, consider
1873 ** it constant. */
1880 }
1881 }
1882 }
1884 /* Check if pExpr is a sub-select. If so, consider it variable. */
1888 }
1891 }
1893 /*
1894 ** Walk the expression tree passed as the first argument. Return non-zero
1895 ** if the expression consists entirely of constants or copies of terms
1896 ** in pGroupBy that sort with the BINARY collation sequence.
1897 **
1898 ** This routine is used to determine if a term of the HAVING clause can
1899 ** be promoted into the WHERE clause. In order for such a promotion to work,
1900 ** the value of the HAVING clause term must be the same for all members of
1901 ** a "group". The requirement that the GROUP BY term must be BINARY
1902 ** assumes that no other collating sequence will have a finer-grained
1903 ** grouping than binary. In other words (A=B COLLATE binary) implies
1904 ** A=B in every other collating sequence. The requirement that the
1905 ** GROUP BY be BINARY is stricter than necessary. It would also work
1906 ** to promote HAVING clauses that use the same alternative collating
1907 ** sequence as the GROUP BY term, but that is much harder to check,
1908 ** alternative collating sequences are uncommon, and this is only an
1909 ** optimization, so we take the easy way out and simply require the
1910 ** GROUP BY to use the BINARY collating sequence.
1911 */
1913 Walker w;
1921 }
1923 /*
1924 ** Walk an expression tree. Return non-zero if the expression is constant
1925 ** or a function call with constant arguments. Return and 0 if there
1926 ** are any variables.
1927 **
1928 ** For the purposes of this function, a double-quoted string (ex: "abc")
1929 ** is considered a variable but a single-quoted string (ex: 'abc') is
1930 ** a constant.
1931 */
1935 }
1937 #ifdef SQLITE_ENABLE_CURSOR_HINTS
1938 /*
1939 ** Walk an expression tree. Return 1 if the expression contains a
1940 ** subquery of some kind. Return 0 if there are no subqueries.
1941 */
1943 Walker w;
1947 #ifdef SQLITE_DEBUG
1949 #endif
1952 }
1953 #endif
1955 /*
1956 ** If the expression p codes a constant integer that is small enough
1957 ** to fit in a 32-bit integer, return 1 and put the value of the integer
1958 ** in *pValue. If the expression is not an integer or if it is too big
1959 ** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
1960 */
1965 /* If an expression is an integer literal that fits in a signed 32-bit
1966 ** integer, then the EP_IntValue flag will have already been set */
1973 }
1978 }
1985 }
1987 }
1989 }
1991 }
1993 /*
1994 ** Return FALSE if there is no chance that the expression can be NULL.
1995 **
1996 ** If the expression might be NULL or if the expression is too complex
1997 ** to tell return TRUE.
1998 **
1999 ** This routine is used as an optimization, to skip OP_IsNull opcodes
2000 ** when we know that a value cannot be NULL. Hence, a false positive
2001 ** (returning TRUE when in fact the expression can never be NULL) might
2002 ** be a small performance hit but is otherwise harmless. On the other
2003 ** hand, a false negative (returning FALSE when the result could be NULL)
2004 ** will likely result in an incorrect answer. So when in doubt, return
2005 ** TRUE.
2006 */
2008 u8 op;
2024 }
2025 }
2027 /*
2028 ** Return TRUE if the given expression is a constant which would be
2029 ** unchanged by OP_Affinity with the affinity given in the second
2030 ** argument.
2031 **
2032 ** This routine is used to determine if the OP_Affinity operation
2033 ** can be omitted. When in doubt return FALSE. A false negative
2034 ** is harmless. A false positive, however, can result in the wrong
2035 ** answer.
2036 */
2038 u8 op;
2046 }
2049 }
2052 }
2055 }
2060 }
2063 }
2064 }
2065 }
2067 /*
2068 ** Return TRUE if the given string is a row-id column name.
2069 */
2075 }
2077 /*
2078 ** pX is the RHS of an IN operator. If pX is a SELECT statement
2079 ** that can be simplified to a direct table access, then return
2080 ** a pointer to the SELECT statement. If pX is not a SELECT statement,
2081 ** or if the SELECT statement needs to be manifested into a transient
2082 ** table, then return NULL.
2083 */
2084 #ifndef SQLITE_OMIT_SUBQUERY
2099 }
2114 /* All SELECT results must be columns. */
2119 }
2121 }
2124 #ifndef SQLITE_OMIT_SUBQUERY
2125 /*
2126 ** Generate code that checks the left-most column of index table iCur to see if
2127 ** it contains any NULL entries. Cause the register at regHasNull to be set
2128 ** to a non-NULL value if iCur contains no NULLs. Cause register regHasNull
2129 ** to be set to NULL if iCur contains one or more NULL values.
2130 */
2139 }
2140 #endif
2143 #ifndef SQLITE_OMIT_SUBQUERY
2144 /*
2145 ** The argument is an IN operator with a list (not a subquery) on the
2146 ** right-hand side. Return TRUE if that list is constant.
2147 */
2157 }
2158 #endif
2160 /*
2161 ** This function is used by the implementation of the IN (...) operator.
2162 ** The pX parameter is the expression on the RHS of the IN operator, which
2163 ** might be either a list of expressions or a subquery.
2164 **
2165 ** The job of this routine is to find or create a b-tree object that can
2166 ** be used either to test for membership in the RHS set or to iterate through
2167 ** all members of the RHS set, skipping duplicates.
2168 **
2169 ** A cursor is opened on the b-tree object that is the RHS of the IN operator
2170 ** and pX->iTable is set to the index of that cursor.
2171 **
2172 ** The returned value of this function indicates the b-tree type, as follows:
2173 **
2174 ** IN_INDEX_ROWID - The cursor was opened on a database table.
2175 ** IN_INDEX_INDEX_ASC - The cursor was opened on an ascending index.
2176 ** IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
2177 ** IN_INDEX_EPH - The cursor was opened on a specially created and
2178 ** populated epheremal table.
2179 ** IN_INDEX_NOOP - No cursor was allocated. The IN operator must be
2180 ** implemented as a sequence of comparisons.
2181 **
2182 ** An existing b-tree might be used if the RHS expression pX is a simple
2183 ** subquery such as:
2184 **
2185 ** SELECT <column1>, <column2>... FROM <table>
2186 **
2187 ** If the RHS of the IN operator is a list or a more complex subquery, then
2188 ** an ephemeral table might need to be generated from the RHS and then
2189 ** pX->iTable made to point to the ephemeral table instead of an
2190 ** existing table.
2191 **
2192 ** The inFlags parameter must contain exactly one of the bits
2193 ** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP. If inFlags contains
2194 ** IN_INDEX_MEMBERSHIP, then the generated table will be used for a
2195 ** fast membership test. When the IN_INDEX_LOOP bit is set, the
2196 ** IN index will be used to loop over all values of the RHS of the
2197 ** IN operator.
2198 **
2199 ** When IN_INDEX_LOOP is used (and the b-tree will be used to iterate
2200 ** through the set members) then the b-tree must not contain duplicates.
2201 ** An epheremal table must be used unless the selected columns are guaranteed
2202 ** to be unique - either because it is an INTEGER PRIMARY KEY or due to
2203 ** a UNIQUE constraint or index.
2204 **
2205 ** When IN_INDEX_MEMBERSHIP is used (and the b-tree will be used
2206 ** for fast set membership tests) then an epheremal table must
2207 ** be used unless <columns> is a single INTEGER PRIMARY KEY column or an
2208 ** index can be found with the specified <columns> as its left-most.
2209 **
2210 ** If the IN_INDEX_NOOP_OK and IN_INDEX_MEMBERSHIP are both set and
2211 ** if the RHS of the IN operator is a list (not a subquery) then this
2212 ** routine might decide that creating an ephemeral b-tree for membership
2213 ** testing is too expensive and return IN_INDEX_NOOP. In that case, the
2214 ** calling routine should implement the IN operator using a sequence
2215 ** of Eq or Ne comparison operations.
2216 **
2217 ** When the b-tree is being used for membership tests, the calling function
2218 ** might need to know whether or not the RHS side of the IN operator
2219 ** contains a NULL. If prRhsHasNull is not a NULL pointer and
2220 ** if there is any chance that the (...) might contain a NULL value at
2221 ** runtime, then a register is allocated and the register number written
2222 ** to *prRhsHasNull. If there is no chance that the (...) contains a
2223 ** NULL value, then *prRhsHasNull is left unchanged.
2224 **
2225 ** If a register is allocated and its location stored in *prRhsHasNull, then
2226 ** the value in that register will be NULL if the b-tree contains one or more
2227 ** NULL values, and it will be some non-NULL value if the b-tree contains no
2228 ** NULL values.
2229 **
2230 ** If the aiMap parameter is not NULL, it must point to an array containing
2231 ** one element for each column returned by the SELECT statement on the RHS
2232 ** of the IN(...) operator. The i'th entry of the array is populated with the
2233 ** offset of the index column that matches the i'th column returned by the
2234 ** SELECT. For example, if the expression and selected index are:
2235 **
2236 ** (?,?,?) IN (SELECT a, b, c FROM t1)
2237 ** CREATE INDEX i1 ON t1(b, c, a);
2238 **
2239 ** then aiMap[] is populated with {2, 0, 1}.
2240 */
2241 #ifndef SQLITE_OMIT_SUBQUERY
2248 ){
2258 /* If the RHS of this IN(...) operator is a SELECT, and if it matters
2259 ** whether or not the SELECT result contains NULL values, check whether
2260 ** or not NULL is actually possible (it may not be, for example, due
2261 ** to NOT NULL constraints in the schema). If no NULL values are possible,
2262 ** set prRhsHasNull to 0 before continuing. */
2268 }
2271 }
2272 }
2274 /* Check to see if an existing table or index can be used to
2275 ** satisfy the query. This is preferable to generating a new
2276 ** ephemeral table. */
2289 /* Code an OP_Transaction and OP_TableLock for <table>. */
2296 /* The "x IN (SELECT rowid FROM table)" case */
2309 /* Check that the affinity that will be used to perform each
2310 ** comparison is the same as the affinity of each column in table
2311 ** on the RHS of the IN operator. If it not, it is not possible to
2312 ** use any index of the RHS table. */
2324 /* sqlite3CompareAffinity() only returns TEXT if one side or the
2325 ** other has no affinity and the other side is TEXT. Hence,
2326 ** the only way for cmpaff to be TEXT is for idxaff to be TEXT
2327 ** and for the term on the LHS of the IN to have no affinity. */
2332 }
2333 }
2336 /* Search for an existing index that will work for this IN operator */
2341 /* Maximum nColumn is BMS-2, not BMS-1, so that we can compute
2342 ** BITMASK(nExpr) without overflowing */
2349 ){
2351 }
2352 }
2367 }
2369 }
2375 }
2379 /* If we reach this point, that means the index pIdx is usable */
2381 #ifndef SQLITE_OMIT_EXPLAIN
2384 P4_DYNAMIC);
2385 #endif
2393 #ifdef SQLITE_ENABLE_COLUMN_USED_MASK
2397 #endif
2401 }
2402 }
2404 }
2410 /* If no preexisting index is available for the IN clause
2411 ** and IN_INDEX_NOOP is an allowed reply
2412 ** and the RHS of the IN operator is a list, not a subquery
2413 ** and the RHS is not constant or has two or fewer terms,
2414 ** then it is not worth creating an ephemeral table to evaluate
2415 ** the IN operator so return IN_INDEX_NOOP.
2416 */
2421 ){
2423 }
2426 /* Could not find an existing table or index to use as the RHS b-tree.
2427 ** We will have to generate an ephemeral table to do the job.
2428 */
2436 }
2439 }
2444 }
2450 }
2452 }
2453 #endif
2455 #ifndef SQLITE_OMIT_SUBQUERY
2456 /*
2457 ** Argument pExpr is an (?, ?...) IN(...) expression. This
2458 ** function allocates and returns a nul-terminated string containing
2459 ** the affinities to be used for each column of the comparison.
2460 **
2461 ** It is the responsibility of the caller to ensure that the returned
2462 ** string is eventually freed using sqlite3DbFree().
2463 */
2481 }
2482 }
2484 }
2486 }
2487 #endif
2489 #ifndef SQLITE_OMIT_SUBQUERY
2490 /*
2491 ** Load the Parse object passed as the first argument with an error
2492 ** message of the form:
2493 **
2494 ** "sub-select returns N columns - expected M"
2495 */
2499 }
2500 #endif
2502 /*
2503 ** Expression pExpr is a vector that has been used in a context where
2504 ** it is not permitted. If pExpr is a sub-select vector, this routine
2505 ** loads the Parse object with a message of the form:
2506 **
2507 ** "sub-select returns N columns - expected 1"
2508 **
2509 ** Or, if it is a regular scalar vector:
2510 **
2511 ** "row value misused"
2512 */
2514 #ifndef SQLITE_OMIT_SUBQUERY
2518 #endif
2519 {
2521 }
2522 }
2524 /*
2525 ** Generate code for scalar subqueries used as a subquery expression, EXISTS,
2526 ** or IN operators. Examples:
2527 **
2528 ** (SELECT a FROM b) -- subquery
2529 ** EXISTS (SELECT a FROM b) -- EXISTS subquery
2530 ** x IN (4,5,11) -- IN operator with list on right-hand side
2531 ** x IN (SELECT a FROM b) -- IN operator with subquery on the right
2532 **
2533 ** The pExpr parameter describes the expression that contains the IN
2534 ** operator or subquery.
2535 **
2536 ** If parameter isRowid is non-zero, then expression pExpr is guaranteed
2537 ** to be of the form "<rowid> IN (?, ?, ?)", where <rowid> is a reference
2538 ** to some integer key column of a table B-Tree. In this case, use an
2539 ** intkey B-Tree to store the set of IN(...) values instead of the usual
2540 ** (slower) variable length keys B-Tree.
2541 **
2542 ** If rMayHaveNull is non-zero, that means that the operation is an IN
2543 ** (not a SELECT or EXISTS) and that the RHS might contains NULLs.
2544 ** All this routine does is initialize the register given by rMayHaveNull
2545 ** to NULL. Calling routines will take care of changing this register
2546 ** value to non-NULL if the RHS is NULL-free.
2547 **
2548 ** For a SELECT or EXISTS operator, return the register that holds the
2549 ** result. For a multi-column SELECT, the result is stored in a contiguous
2550 ** array of registers and the return value is the register of the left-most
2551 ** result column. Return 0 for IN operators or if an error occurs.
2552 */
2553 #ifndef SQLITE_OMIT_SUBQUERY
2559 ){
2566 /* The evaluation of the IN/EXISTS/SELECT must be repeated every time it
2567 ** is encountered if any of the following is true:
2568 **
2569 ** * The right-hand side is a correlated subquery
2570 ** * The right-hand side is an expression list containing variables
2571 ** * We are inside a trigger
2572 **
2573 ** If all of the above are false, then we can run this code just once
2574 ** save the results, and reuse the same result on subsequent invocations.
2575 */
2578 }
2580 #ifndef SQLITE_OMIT_EXPLAIN
2585 pParse->iNextSelectId
2586 );
2588 }
2589 #endif
2601 /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
2602 ** expression it is handled the same way. An ephemeral table is
2603 ** filled with index keys representing the results from the
2604 ** SELECT or the <exprlist>.
2605 **
2606 ** If the 'x' expression is a column value, or the SELECT...
2607 ** statement returns a column value, then the affinity of that
2608 ** column is used to build the index keys. If both 'x' and the
2609 ** SELECT... statement are columns, then numeric affinity is used
2610 ** if either column has NUMERIC or INTEGER affinity. If neither
2611 ** 'x' nor the SELECT... statement are columns, then numeric affinity
2612 ** is used.
2613 */
2620 /* Case 1: expr IN (SELECT ...)
2621 **
2622 ** Generate code to write the results of the select into the temporary
2623 ** table allocated and opened above.
2624 */
2629 /* If the LHS and RHS of the IN operator do not match, that
2630 ** error will have been caught long before we reach this point. */
2632 SelectDest dest;
2643 }
2653 );
2654 }
2655 }
2657 /* Case 2: expr IN (exprlist)
2658 **
2659 ** For each expression, build an index key from the evaluation and
2660 ** store it in the temporary table. If <expr> is a column, then use
2661 ** that columns affinity when building index keys. If <expr> is not
2662 ** a column, use numeric affinity.
2663 */
2673 }
2677 }
2679 /* Loop through each expression in <exprlist>. */
2687 /* If the expression is not constant then we will need to
2688 ** disable the test that was generated above that makes sure
2689 ** this code only executes once. Because for a non-constant
2690 ** expression we need to rerun this code each time.
2691 */
2695 }
2697 /* Evaluate the expression and insert it into the temp table */
2711 }
2712 }
2713 }
2716 }
2719 }
2721 }
2726 /* Case 3: (SELECT ... FROM ...)
2727 ** or: EXISTS(SELECT ... FROM ...)
2728 **
2729 ** For a SELECT, generate code to put the values for all columns of
2730 ** the first row into an array of registers and return the index of
2731 ** the first register.
2732 **
2733 ** If this is an EXISTS, write an integer 0 (not exists) or 1 (exists)
2734 ** into a register and return that register number.
2735 **
2736 ** In both cases, the query is augmented with "LIMIT 1". Any
2737 ** preexisting limit is discarded in place of the new LIMIT 1.
2738 */
2762 }
2770 }
2774 }
2775 }
2779 }
2783 }
2787 }
2790 #ifndef SQLITE_OMIT_SUBQUERY
2791 /*
2792 ** Expr pIn is an IN(...) expression. This function checks that the
2793 ** sub-select on the RHS of the IN() operator has the same number of
2794 ** columns as the vector on the LHS. Or, if the RHS of the IN() is not
2795 ** a sub-query, that the LHS is a vector of size 1.
2796 */
2803 }
2807 }
2809 }
2810 #endif
2812 #ifndef SQLITE_OMIT_SUBQUERY
2813 /*
2814 ** Generate code for an IN expression.
2815 **
2816 ** x IN (SELECT ...)
2817 ** x IN (value, value, ...)
2818 **
2819 ** The left-hand side (LHS) is a scalar or vector expression. The
2820 ** right-hand side (RHS) is an array of zero or more scalar values, or a
2821 ** subquery. If the RHS is a subquery, the number of result columns must
2822 ** match the number of columns in the vector on the LHS. If the RHS is
2823 ** a list of values, the LHS must be a scalar.
2824 **
2825 ** The IN operator is true if the LHS value is contained within the RHS.
2826 ** The result is false if the LHS is definitely not in the RHS. The
2827 ** result is NULL if the presence of the LHS in the RHS cannot be
2828 ** determined due to NULLs.
2829 **
2830 ** This routine generates code that jumps to destIfFalse if the LHS is not
2831 ** contained within the RHS. If due to NULLs we cannot determine if the LHS
2832 ** is contained in the RHS then jump to destIfNull. If the LHS is contained
2833 ** within the RHS then fall through.
2834 **
2835 ** See the separate in-operator.md documentation file in the canonical
2836 ** SQLite source tree for additional information.
2837 */
2843 ){
2867 );
2870 /* Attempt to compute the RHS. After this step, if anything other than
2871 ** IN_INDEX_NOOP is returned, the table opened ith cursor pExpr->iTable
2872 ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
2873 ** the RHS has not yet been coded. */
2883 );
2884 #ifdef SQLITE_DEBUG
2885 /* Confirm that aiMap[] contains nVector integer values between 0 and
2886 ** nVector-1. */
2891 }
2892 #endif
2894 /* Code the LHS, the <expr> from "<expr> IN (...)". If the LHS is a
2895 ** vector, then it is stored in an array of nVector registers starting
2896 ** at r1.
2897 **
2898 ** sqlite3FindInIndex() might have reordered the fields of the LHS vector
2899 ** so that the fields are in the same order as an existing index. The
2900 ** aiMap[] array contains a mapping from the original LHS field order to
2901 ** the field order that matches the RHS index.
2902 */
2907 /* LHS fields are not reordered */
2910 /* Need to reorder the LHS fields according to aiMap */
2914 }
2915 }
2917 /* If sqlite3FindInIndex() did not find or create an index that is
2918 ** suitable for evaluating the IN operator, then evaluate using a
2919 ** sequence of comparisons.
2920 **
2921 ** This is step (1) in the in-operator.md optimized algorithm.
2922 */
2934 }
2939 }
2951 }
2953 }
2957 }
2961 }
2963 /* Step 2: Check to see if the LHS contains any NULL columns. If the
2964 ** LHS does contain NULLs then the result must be either FALSE or NULL.
2965 ** We will then skip the binary search of the RHS.
2966 */
2971 }
2977 }
2978 }
2980 /* Step 3. The LHS is now known to be non-NULL. Do the binary search
2981 ** of the RHS using the LHS as a probe. If found, the result is
2982 ** true.
2983 */
2985 /* In this case, the RHS is the ROWID of table b-tree and so we also
2986 ** know that the RHS is non-NULL. Hence, we combine steps 3 and 4
2987 ** into a single opcode. */
2994 /* Combine Step 3 and Step 5 into a single opcode */
2998 }
2999 /* Ordinary Step 3, for the case where FALSE and NULL are distinct */
3002 }
3004 /* Step 4. If the RHS is known to be non-NULL and we did not find
3005 ** an match on the search above, then the result must be FALSE.
3006 */
3010 }
3012 /* Step 5. If we do not care about the difference between NULL and
3013 ** FALSE, then just return false.
3014 */
3017 /* Step 6: Loop through rows of the RHS. Compare each row to the LHS.
3018 ** If any comparison is NULL, then the result is NULL. If all
3019 ** comparisons are FALSE then the final result is FALSE.
3020 **
3021 ** For a scalar LHS, it is sufficient to check just the first row
3022 ** of the RHS.
3023 */
3030 /* For nVector==1, combine steps 6 and 7 by immediately returning
3031 ** FALSE if the first comparison is not NULL */
3033 }
3045 }
3052 /* Step 7: If we reach this point, we know that the result must
3053 ** be false. */
3055 }
3057 /* Jumps here in order to return true. */
3060 sqlite3ExprCodeIN_finished:
3064 sqlite3ExprCodeIN_oom_error:
3067 }
3070 #ifndef SQLITE_OMIT_FLOATING_POINT
3071 /*
3072 ** Generate an instruction that will put the floating point
3073 ** value described by z[0..n-1] into register iMem.
3074 **
3075 ** The z[] string will probably not be zero-terminated. But the
3076 ** z[n] character is guaranteed to be something that does not look
3077 ** like the continuation of the number.
3078 */
3086 }
3087 }
3088 #endif
3091 /*
3092 ** Generate an instruction that will put the integer describe by
3093 ** text z[0..n-1] into register iMem.
3094 **
3095 ** Expr.u.zToken is always UTF8 and zero-terminated.
3096 */
3106 i64 value;
3111 #ifdef SQLITE_OMIT_FLOATING_POINT
3113 #else
3114 #ifndef SQLITE_OMIT_HEX_INTEGER
3118 #endif
3119 {
3121 }
3122 #endif
3126 }
3127 }
3128 }
3130 /*
3131 ** Erase column-cache entry number i
3132 */
3137 }
3138 }
3142 }
3143 }
3146 /*
3147 ** Record in the column cache that a particular column from a
3148 ** particular table is stored in a particular register.
3149 */
3156 /* Unless an error has occurred, register numbers are always positive. */
3160 /* The SQLITE_ColumnCache flag disables the column cache. This is used
3161 ** for testing only - to verify that SQLite always gets the same answer
3162 ** with and without the column cache.
3163 */
3166 /* First replace any existing entry.
3167 **
3168 ** Actually, the way the column cache is currently used, we are guaranteed
3169 ** that the object will never already be in cache. Verify this guarantee.
3170 */
3171 #ifndef NDEBUG
3174 }
3175 #endif
3177 /* If the cache is already full, delete the least recently used entry */
3185 }
3186 }
3190 }
3192 /* Add the new entry to the end of the cache */
3199 }
3201 /*
3202 ** Indicate that registers between iReg..iReg+nReg-1 are being overwritten.
3203 ** Purge the range of registers from the column cache.
3204 */
3212 i++;
3213 }
3214 }
3215 }
3217 /*
3218 ** Remember the current column cache context. Any new entries added
3219 ** added to the column cache after this call are removed when the
3220 ** corresponding pop occurs.
3221 */
3224 #ifdef SQLITE_DEBUG
3227 }
3228 #endif
3229 }
3231 /*
3232 ** Remove from the column cache any entries that were added since the
3233 ** the previous sqlite3ExprCachePush operation. In other words, restore
3234 ** the cache to the state it was in prior the most recent Push.
3235 */
3240 #ifdef SQLITE_DEBUG
3243 }
3244 #endif
3249 i++;
3250 }
3251 }
3252 }
3254 /*
3255 ** When a cached column is reused, make sure that its register is
3256 ** no longer available as a temp register. ticket #3879: that same
3257 ** register might be in the cache in multiple places, so be sure to
3258 ** get them all.
3259 */
3266 }
3267 }
3268 }
3270 /* Generate code that will load into register regOut a value that is
3271 ** appropriate for the iIdxCol-th column of index pIdx.
3272 */
3279 ){
3290 }
3291 }
3293 /*
3294 ** Generate code to extract the value of the iCol-th column of a table.
3295 */
3302 ){
3306 }
3314 }
3316 }
3319 }
3320 }
3322 /*
3323 ** Generate code that will extract the iColumn-th column from
3324 ** table pTab and store the column value in a register.
3325 **
3326 ** An effort is made to store the column value in register iReg. This
3327 ** is not garanteeed for GetColumn() - the result can be stored in
3328 ** any register. But the result is guaranteed to land in register iReg
3329 ** for GetColumnToReg().
3330 **
3331 ** There must be an open cursor to pTab in iTable when this routine
3332 ** is called. If iColumn<0 then code is generated that extracts the rowid.
3333 */
3340 u8 p5 /* P5 value for OP_Column + FLAGS */
3341 ){
3351 }
3352 }
3359 }
3361 }
3368 ){
3371 }
3374 /*
3375 ** Clear all column cache entries.
3376 */
3380 #ifdef SQLITE_DEBUG
3383 }
3384 #endif
3388 ){
3390 }
3391 }
3393 }
3395 /*
3396 ** Record the fact that an affinity change has occurred on iCount
3397 ** registers starting with iStart.
3398 */
3401 }
3403 /*
3404 ** Generate code to move content from registers iFrom...iFrom+nReg-1
3405 ** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
3406 */
3411 }
3413 #if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
3414 /*
3415 ** Return true if any register in the range iFrom..iTo (inclusive)
3416 ** is used as part of the column cache.
3417 **
3418 ** This routine is used within assert() and testcase() macros only
3419 ** and does not appear in a normal build.
3420 */
3427 }
3429 }
3433 /*
3434 ** Convert a scalar expression node to a TK_REGISTER referencing
3435 ** register iReg. The caller must ensure that iReg already contains
3436 ** the correct value for the expression.
3437 */
3443 }
3445 /*
3446 ** Evaluate an expression (either a vector or a scalar expression) and store
3447 ** the result in continguous temporary registers. Return the index of
3448 ** the first register used to store the result.
3449 **
3450 ** If the returned result register is a temporary scalar, then also write
3451 ** that register number into *piFreeable. If the returned result register
3452 ** is not a temporary or if the expression is a vector set *piFreeable
3453 ** to 0.
3454 */
3463 #if SQLITE_OMIT_SUBQUERY
3465 #else
3467 #endif
3474 }
3475 }
3476 }
3478 }
3481 /*
3482 ** Generate code into the current Vdbe to evaluate the given
3483 ** expression. Attempt to store the results in register "target".
3484 ** Return the register where results are stored.
3485 **
3486 ** With this routine, there is no guarantee that results will
3487 ** be stored in target. The result might be stored in some other
3488 ** register if it is convenient to do so. The calling function
3489 ** must check the return code and move the results to the desired
3490 ** register.
3491 */
3506 }
3512 }
3524 }
3525 /* Otherwise, fall thru into the TK_COLUMN case */
3526 }
3531 /* Generating CHECK constraints or inserting into partial index */
3534 /* Coding an expression that is part of an index where column names
3535 ** in the index refer to the table to which the index belongs */
3537 }
3538 }
3542 }
3546 }
3547 #ifndef SQLITE_OMIT_FLOATING_POINT
3552 }
3553 #endif
3558 }
3562 }
3563 #ifndef SQLITE_OMIT_BLOB_LITERAL
3577 }
3578 #endif
3589 }
3591 }
3594 }
3595 #ifndef SQLITE_OMIT_CAST
3597 /* Expressions of the form: CAST(pLeft AS token) */
3602 }
3608 }
3614 /* fall-through */
3637 }
3639 }
3669 }
3676 #ifndef SQLITE_OMIT_FLOATING_POINT
3681 #endif
3690 }
3692 }
3701 }
3716 }
3724 }
3726 }
3739 /* SQL functions can be expensive. So try to move constant functions
3740 ** out of the inner loop, even if that means an extra OP_Copy. */
3742 }
3748 }
3753 #ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
3756 }
3757 #endif
3761 }
3763 /* Attempt a direct implementation of the built-in COALESCE() and
3764 ** IFNULL() functions. This avoids unnecessary evaluation of
3765 ** arguments past the first non-NULL argument.
3766 */
3778 }
3781 }
3783 /* The UNLIKELY() function is a no-op. The result is the value
3784 ** of the first argument.
3785 */
3789 }
3791 #ifdef SQLITE_DEBUG
3792 /* The AFFINITY() function evaluates to a string that describes
3793 ** the type affinity of the argument. This is used for testing of
3794 ** the SQLite type logic.
3795 */
3804 }
3805 #endif
3811 }
3814 }
3815 }
3822 }
3824 /* For length() and typeof() functions with a column argument,
3825 ** set the P5 parameter to the OP_Column opcode to OPFLAG_LENGTHARG
3826 ** or OPFLAG_TYPEOFARG respectively, to avoid unnecessary data
3827 ** loading.
3828 */
3830 u8 exprOp;
3840 }
3841 }
3849 }
3850 #ifndef SQLITE_OMIT_VIRTUALTABLE
3851 /* Possibly overload the function if the first argument is
3852 ** a virtual table column.
3853 **
3854 ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
3855 ** second argument, not the first, as the argument to test to
3856 ** see if it is a column in a virtual table. This is done because
3857 ** the left operand of infix functions (the operand we want to
3858 ** control overloading) ends up as the second argument to the
3859 ** function. The expression "A glob B" is equivalent to
3860 ** "glob(B,A). We want to use the A in "A glob B" to test
3861 ** for function overloading. But we use the B term in "glob(B,A)".
3862 */
3867 }
3868 #endif
3872 }
3878 }
3880 }
3881 #ifndef SQLITE_OMIT_SUBQUERY
3891 }
3893 }
3898 }
3902 ){
3905 }
3907 }
3918 }
3922 /*
3923 ** x BETWEEN y AND z
3924 **
3925 ** This is equivalent to
3926 **
3927 ** x>=y AND x<=z
3928 **
3929 ** X is stored in pExpr->pLeft.
3930 ** Y is stored in pExpr->pList->a[0].pExpr.
3931 ** Z is stored in pExpr->pList->a[1].pExpr.
3932 */
3936 }
3941 }
3944 /* If the opcode is TK_TRIGGER, then the expression is a reference
3945 ** to a column in the new.* or old.* pseudo-tables available to
3946 ** trigger programs. In this case Expr.iTable is set to 1 for the
3947 ** new.* pseudo-table, or 0 for the old.* pseudo-table. Expr.iColumn
3948 ** is set to the column of the pseudo-table to read, or to -1 to
3949 ** read the rowid field.
3950 **
3951 ** The expression is implemented using an OP_Param opcode. The p1
3952 ** parameter is set to 0 for an old.rowid reference, or to (i+1)
3953 ** to reference another column of the old.* pseudo-table, where
3954 ** i is the index of the column. For a new.rowid reference, p1 is
3955 ** set to (n+1), where n is the number of columns in each pseudo-table.
3956 ** For a reference to any other column in the new.* pseudo-table, p1
3957 ** is set to (n+2+i), where n and i are as defined previously. For
3958 ** example, if the table on which triggers are being fired is
3959 ** declared as:
3960 **
3961 ** CREATE TABLE t1(a, b);
3962 **
3963 ** Then p1 is interpreted as follows:
3964 **
3965 ** p1==0 -> old.rowid p1==3 -> new.rowid
3966 ** p1==1 -> old.a p1==4 -> new.a
3967 ** p1==2 -> old.b p1==5 -> new.b
3968 */
3981 target
3982 ));
3984 #ifndef SQLITE_OMIT_FLOATING_POINT
3985 /* If the column has REAL affinity, it may currently be stored as an
3986 ** integer. Use OP_RealAffinity to make sure it is really real.
3987 **
3988 ** EVIDENCE-OF: R-60985-57662 SQLite will convert the value back to
3989 ** floating point when extracting it from the record. */
3992 ){
3994 }
3995 #endif
3997 }
4002 }
4013 }
4015 /*
4016 ** Form A:
4017 ** CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
4018 **
4019 ** Form B:
4020 ** CASE WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
4021 **
4022 ** Form A is can be transformed into the equivalent form B as follows:
4023 ** CASE WHEN x=e1 THEN r1 WHEN x=e2 THEN r2 ...
4024 ** WHEN x=eN THEN rN ELSE y END
4025 **
4026 ** X (if it exists) is in pExpr->pLeft.
4027 ** Y is in the last element of pExpr->x.pList if pExpr->x.pList->nExpr is
4028 ** odd. The Y is also optional. If the number of elements in x.pList
4029 ** is even, then Y is omitted and the "otherwise" result is NULL.
4030 ** Ei is in pExpr->pList->a[i*2] and Ri is pExpr->pList->a[i*2+1].
4031 **
4032 ** The result of the expression is the Ri for the first matching Ei,
4033 ** or if there is no matching Ei, the ELSE term Y, or if there is
4034 ** no ELSE term, NULL.
4035 */
4063 /* Ticket b351d95f9cd5ef17e9d9dbae18f5ca8611190001:
4064 ** The value in regFree1 might get SCopy-ed into the file result.
4065 ** So make sure that the regFree1 register is not reused for other
4066 ** purposes and possibly overwritten. */
4068 }
4076 }
4085 }
4092 }
4097 }
4098 #ifndef SQLITE_OMIT_TRIGGER
4104 );
4109 }
4112 }
4121 }
4124 }
4125 #endif
4126 }
4130 }
4132 /*
4133 ** Factor out the code of the given expression to initialization time.
4134 **
4135 ** If regDest>=0 then the result is always stored in that register and the
4136 ** result is not reusable. If regDest<0 then this routine is free to
4137 ** store the value whereever it wants. The register where the expression
4138 ** is stored is returned. When regDest<0, two identical expressions will
4139 ** code to the same register.
4140 */
4145 ){
4155 }
4156 }
4157 }
4165 }
4168 }
4170 /*
4171 ** Generate code to evaluate an expression and store the results
4172 ** into a register. Return the register number where the results
4173 ** are stored.
4174 **
4175 ** If the register is a temporary register that can be deallocated,
4176 ** then write its number into *pReg. If the result register is not
4177 ** a temporary, then set *pReg to zero.
4178 **
4179 ** If pExpr is a constant, then this routine might generate this
4180 ** code to fill the register in the initialization section of the
4181 ** VDBE program, in order to factor it out of the evaluation loop.
4182 */
4189 ){
4200 }
4201 }
4203 }
4205 /*
4206 ** Generate code that will evaluate expression pExpr and store the
4207 ** results in register target. The results are guaranteed to appear
4208 ** in register target.
4209 */
4221 }
4222 }
4223 }
4225 /*
4226 ** Make a transient copy of expression pExpr and then code it using
4227 ** sqlite3ExprCode(). This routine works just like sqlite3ExprCode()
4228 ** except that the input expression is guaranteed to be unchanged.
4229 */
4235 }
4237 /*
4238 ** Generate code that will evaluate expression pExpr and store the
4239 ** results in register target. The results are guaranteed to appear
4240 ** in register target. If the expression is constant, then this routine
4241 ** might choose to code the expression at initialization time.
4242 */
4248 }
4249 }
4251 /*
4252 ** Generate code that evaluates the given expression and puts the result
4253 ** in register target.
4254 **
4255 ** Also make a copy of the expression results into another "cache" register
4256 ** and modify the expression so that the next time it is evaluated,
4257 ** the result is a copy of the cache register.
4258 **
4259 ** This routine is used for expressions that are used multiple
4260 ** times. They are evaluated once and the results of the expression
4261 ** are reused.
4262 */
4273 }
4275 /*
4276 ** Generate code that pushes the value of every element of the given
4277 ** expression list into a sequence of registers beginning at target.
4278 **
4279 ** Return the number of elements evaluated. The number returned will
4280 ** usually be pList->nExpr but might be reduced if SQLITE_ECEL_OMITREF
4281 ** is defined.
4282 **
4283 ** The SQLITE_ECEL_DUP flag prevents the arguments from being
4284 ** filled using OP_SCopy. OP_Copy must be used instead.
4285 **
4286 ** The SQLITE_ECEL_FACTOR argument allows constant arguments to be
4287 ** factored out into initialization code.
4288 **
4289 ** The SQLITE_ECEL_REF flag means that expressions in the list with
4290 ** ExprList.a[].u.x.iOrderByCol>0 have already been evaluated and stored
4291 ** in registers at srcReg, and so the value can be copied from there.
4292 ** If SQLITE_ECEL_OMITREF is also set, then the values with u.x.iOrderByCol>0
4293 ** are simply omitted rather than being copied from srcReg.
4294 */
4300 u8 flags /* SQLITE_ECEL_* flags */
4301 ){
4315 i--;
4316 n--;
4319 }
4330 ){
4334 }
4335 }
4336 }
4337 }
4339 }
4341 /*
4342 ** Generate code for a BETWEEN operator.
4343 **
4344 ** x BETWEEN y AND z
4345 **
4346 ** The above is equivalent to
4347 **
4348 ** x>=y AND x<=z
4349 **
4350 ** Code it as such, taking care to do the common subexpression
4351 ** elimination of x.
4352 **
4353 ** The xJumpIf parameter determines details:
4354 **
4355 ** NULL: Store the boolean result in reg[dest]
4356 ** sqlite3ExprIfTrue: Jump to dest if true
4357 ** sqlite3ExprIfFalse: Jump to dest if false
4358 **
4359 ** The jumpIfNull parameter is ignored if xJumpIf is NULL.
4360 */
4367 ){
4394 /* Mark the expression is being from the ON or USING clause of a join
4395 ** so that the sqlite3ExprCodeTarget() routine will not attempt to move
4396 ** it into the Parse.pConstExpr list. We should use a new bit for this,
4397 ** for clarity, but we are out of bits in the Expr.flags field so we
4398 ** have to reuse the EP_FromJoin bit. Bummer. */
4401 }
4404 /* Ensure adequate test coverage */
4414 }
4416 /*
4417 ** Generate code for a boolean expression such that a jump is made
4418 ** to the label "dest" if the expression is true but execution
4419 ** continues straight thru if the expression is false.
4420 **
4421 ** If the expression evaluates to NULL (neither true nor false), then
4422 ** take the jump if the jumpIfNull flag is SQLITE_JUMPIFNULL.
4423 **
4424 ** This code depends on the fact that certain token values (ex: TK_EQ)
4425 ** are the same as opcode values (ex: OP_Eq) that implement the corresponding
4426 ** operation. Special comments in vdbe.c and the mkopcodeh.awk script in
4427 ** the make process cause these values to align. Assert()s in the code
4428 ** below verify that the numbers are aligned correctly.
4429 */
4451 }
4459 }
4464 }
4471 /* Fall thru */
4497 }
4508 }
4513 }
4514 #ifndef SQLITE_OMIT_SUBQUERY
4522 }
4523 #endif
4525 default_expr:
4529 /* No-op */
4536 }
4538 }
4539 }
4542 }
4544 /*
4545 ** Generate code for a boolean expression such that a jump is made
4546 ** to the label "dest" if the expression is false but execution
4547 ** continues straight thru if the expression is true.
4548 **
4549 ** If the expression evaluates to NULL (neither true nor false) then
4550 ** jump if jumpIfNull is SQLITE_JUMPIFNULL or fall through if jumpIfNull
4551 ** is 0.
4552 */
4564 /* The value of pExpr->op and op are related as follows:
4565 **
4566 ** pExpr->op op
4567 ** --------- ----------
4568 ** TK_ISNULL OP_NotNull
4569 ** TK_NOTNULL OP_IsNull
4570 ** TK_NE OP_Eq
4571 ** TK_EQ OP_Ne
4572 ** TK_GT OP_Le
4573 ** TK_LE OP_Gt
4574 ** TK_GE OP_Lt
4575 ** TK_LT OP_Ge
4576 **
4577 ** For other values of pExpr->op, op is undefined and unused.
4578 ** The value of TK_ and OP_ constants are arranged such that we
4579 ** can compute the mapping above using the following expression.
4580 ** Assert()s verify that the computation is correct.
4581 */
4584 /* Verify correct alignment of TK_ and OP_ constants
4585 */
4603 }
4613 }
4618 }
4625 /* Fall thru */
4651 }
4660 }
4665 }
4666 #ifndef SQLITE_OMIT_SUBQUERY
4674 }
4676 }
4677 #endif
4679 default_expr:
4683 /* no-op */
4690 }
4692 }
4693 }
4696 }
4698 /*
4699 ** Like sqlite3ExprIfFalse() except that a copy is made of pExpr before
4700 ** code generation, and that copy is deleted after code generation. This
4701 ** ensures that the original pExpr is unchanged.
4702 */
4708 }
4710 }
4712 /*
4713 ** Expression pVar is guaranteed to be an SQL variable. pExpr may be any
4714 ** type of expression.
4715 **
4716 ** If pExpr is a simple SQL value - an integer, real, string, blob
4717 ** or NULL value - then the VDBE currently being prepared is configured
4718 ** to re-prepare each time a new value is bound to variable pVar.
4719 **
4720 ** Additionally, if pExpr is a simple SQL value and the value is the
4721 ** same as that currently bound to variable pVar, non-zero is returned.
4722 ** Otherwise, if the values are not the same or if pExpr is not a simple
4723 ** SQL value, zero is returned.
4724 */
4738 }
4740 }
4743 }
4746 }
4748 /*
4749 ** Do a deep comparison of two expression trees. Return 0 if the two
4750 ** expressions are completely identical. Return 1 if they differ only
4751 ** by a COLLATE operator at the top level. Return 2 if there are differences
4752 ** other than the top-level COLLATE operator.
4753 **
4754 ** If any subelement of pB has Expr.iTable==(-1) then it is allowed
4755 ** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
4756 **
4757 ** The pA side might be using TK_REGISTER. If that is the case and pB is
4758 ** not using TK_REGISTER but is otherwise equivalent, then still return 0.
4759 **
4760 ** Sometimes this routine will return 2 even if the two expressions
4761 ** really are equivalent. If we cannot prove that the expressions are
4762 ** identical, we return 2 just to be safe. So if this routine
4763 ** returns 2, then you do not really know for certain if the two
4764 ** expressions are the same. But if you get a 0 or 1 return, then you
4765 ** can be sure the expressions are the same. In the places where
4766 ** this routine is used, it does not hurt to get an extra 2 - that
4767 ** just might result in some slightly slower code. But returning
4768 ** an incorrect 0 or 1 could lead to a malfunction.
4769 **
4770 ** If pParse is not NULL then TK_VARIABLE terms in pA with bindings in
4771 ** pParse->pReprepare can be matched against literals in pB. The
4772 ** pParse->pVdbe->expmask bitmask is updated for each variable referenced.
4773 ** If pParse is NULL (the normal case) then any TK_VARIABLE term in
4774 ** Argument pParse should normally be NULL. If it is not NULL and pA or
4775 ** pB causes a return value of 2.
4776 */
4778 u32 combinedFlags;
4781 }
4784 }
4789 }
4791 }
4795 }
4798 }
4800 }
4806 }
4807 }
4818 }
4819 }
4821 }
4823 /*
4824 ** Compare two ExprList objects. Return 0 if they are identical and
4825 ** non-zero if they differ in any way.
4826 **
4827 ** If any subelement of pB has Expr.iTable==(-1) then it is allowed
4828 ** to compare equal to an equivalent element in pA with Expr.iTable==iTab.
4829 **
4830 ** This routine might return non-zero for equivalent ExprLists. The
4831 ** only consequence will be disabled optimizations. But this routine
4832 ** must never return 0 if the two ExprList objects are different, or
4833 ** a malfunction will result.
4834 **
4835 ** Two NULL pointers are considered to be the same. But a NULL pointer
4836 ** always differs from a non-NULL pointer.
4837 */
4848 }
4850 }
4852 /*
4853 ** Like sqlite3ExprCompare() except COLLATE operators at the top-level
4854 ** are ignored.
4855 */
4860 iTab);
4861 }
4863 /*
4864 ** Return true if we can prove the pE2 will always be true if pE1 is
4865 ** true. Return false if we cannot complete the proof or if pE2 might
4866 ** be false. Examples:
4867 **
4868 ** pE1: x==5 pE2: x==5 Result: true
4869 ** pE1: x>0 pE2: x==5 Result: false
4870 ** pE1: x=21 pE2: x=21 OR y=43 Result: true
4871 ** pE1: x!=123 pE2: x IS NOT NULL Result: true
4872 ** pE1: x!=?1 pE2: x IS NOT NULL Result: true
4873 ** pE1: x IS NULL pE2: x IS NOT NULL Result: false
4874 ** pE1: x IS ?2 pE2: x IS NOT NULL Reuslt: false
4875 **
4876 ** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
4877 ** Expr.iTable<0 then assume a table number given by iTab.
4878 **
4879 ** If pParse is not NULL, then the values of bound variables in pE1 are
4880 ** compared against literal values in pE2 and pParse->pVdbe->expmask is
4881 ** modified to record which bound variables are referenced. If pParse
4882 ** is NULL, then false will be returned if pE1 contains any bound variables.
4883 **
4884 ** When in doubt, return false. Returning true might give a performance
4885 ** improvement. Returning false might cause a performance reduction, but
4886 ** it will always give the correct answer and is hence always safe.
4887 */
4891 }
4895 ){
4897 }
4902 }
4904 }
4906 /*
4907 ** An instance of the following structure is used by the tree walker
4908 ** to determine if an expression can be evaluated by reference to the
4909 ** index only, without having to do a search for the corresponding
4910 ** table entry. The IdxCover.pIdx field is the index. IdxCover.iCur
4911 ** is the cursor for the table.
4912 */
4916 };
4918 /*
4919 ** Check to see if there are references to columns in table
4920 ** pWalker->u.pIdxCover->iCur can be satisfied using the index
4921 ** pWalker->u.pIdxCover->pIdx.
4922 */
4927 ){
4930 }
4932 }
4934 /*
4935 ** Determine if an index pIdx on table with cursor iCur contains will
4936 ** the expression pExpr. Return true if the index does cover the
4937 ** expression and false if the pExpr expression references table columns
4938 ** that are not found in the index pIdx.
4939 **
4940 ** An index covering an expression means that the expression can be
4941 ** evaluated using only the index and without having to lookup the
4942 ** corresponding table entry.
4943 */
4948 ){
4949 Walker w;
4958 }
4961 /*
4962 ** An instance of the following structure is used by the tree walker
4963 ** to count references to table columns in the arguments of an
4964 ** aggregate function, in order to implement the
4965 ** sqlite3FunctionThisSrc() routine.
4966 */
4971 };
4973 /*
4974 ** Count the number of references to columns.
4975 */
4977 /* The NEVER() on the second term is because sqlite3FunctionUsesThisSrc()
4978 ** is always called before sqlite3ExprAnalyzeAggregates() and so the
4979 ** TK_COLUMNs have not yet been converted into TK_AGG_COLUMN. If
4980 ** sqlite3FunctionUsesThisSrc() is used differently in the future, the
4981 ** NEVER() will need to be removed. */
4989 }
4994 }
4995 }
4997 }
4999 /*
5000 ** Determine if any of the arguments to the pExpr Function reference
5001 ** pSrcList. Return true if they do. Also return true if the function
5002 ** has no arguments or has only constant arguments. Return false if pExpr
5003 ** references columns but not columns of tables found in pSrcList.
5004 */
5006 Walker w;
5017 }
5019 /*
5020 ** Add a new element to the pAggInfo->aCol[] array. Return the index of
5021 ** the new element. Return a negative number if malloc fails.
5022 */
5026 db,
5030 &i
5031 );
5033 }
5035 /*
5036 ** Add a new element to the pAggInfo->aFunc[] array. Return the index of
5037 ** the new element. Return a negative number if malloc fails.
5038 */
5042 db,
5046 &i
5047 );
5049 }
5051 /*
5052 ** This is the xExprCallback for a tree walker. It is used to
5053 ** implement sqlite3ExprAnalyzeAggregates(). See sqlite3ExprAnalyzeAggregates
5054 ** for additional information.
5055 */
5068 /* Check to see if the column is in one of the tables in the FROM
5069 ** clause of the aggregate query */
5076 /* If we reach this point, it means that pExpr refers to a table
5077 ** that is in the FROM clause of the aggregate query.
5078 **
5079 ** Make an entry for the column in pAggInfo->aCol[] if there
5080 ** is not an entry there already.
5081 */
5088 }
5089 }
5092 ){
5111 }
5112 }
5113 }
5116 }
5117 }
5118 /* There is now an entry for pExpr in pAggInfo->aCol[] (either
5119 ** because it was there before or because we just created it).
5120 ** Convert the pExpr to be a TK_AGG_COLUMN referring to that
5121 ** pAggInfo->aCol[] entry.
5122 */
5130 }
5132 }
5136 ){
5137 /* Check to see if pExpr is a duplicate of another aggregate
5138 ** function that is already in the pAggInfo structure
5139 */
5144 }
5145 }
5147 /* pExpr is original. Make a new entry in pAggInfo->aFunc[]
5148 */
5164 }
5165 }
5166 }
5167 /* Make pExpr point to the appropriate pAggInfo->aFunc[] entry
5168 */
5176 }
5177 }
5178 }
5180 }
5185 }
5189 }
5191 /*
5192 ** Analyze the pExpr expression looking for aggregate functions and
5193 ** for variables that need to be added to AggInfo object that pNC->pAggInfo
5194 ** points to. Additional entries are made on the AggInfo object as
5195 ** necessary.
5196 **
5197 ** This routine should only be called after the expression has been
5198 ** analyzed by sqlite3ResolveExprNames().
5199 */
5201 Walker w;
5209 }
5211 /*
5212 ** Call sqlite3ExprAnalyzeAggregates() for every expression in an
5213 ** expression list. Return the number of errors.
5214 **
5215 ** If an error is found, the analysis is cut short.
5216 */
5223 }
5224 }
5225 }
5227 /*
5228 ** Allocate a single new register for use to hold some intermediate result.
5229 */
5233 }
5235 }
5237 /*
5238 ** Deallocate a register, making available for reuse for some other
5239 ** purpose.
5240 **
5241 ** If a register is currently being used by the column cache, then
5242 ** the deallocation is deferred until the column cache line that uses
5243 ** the register becomes stale.
5244 */
5253 }
5254 }
5256 }
5257 }
5259 /*
5260 ** Allocate or deallocate a block of nReg consecutive registers.
5261 */
5274 }
5276 }
5281 }
5286 }
5287 }
5289 /*
5290 ** Mark all temporary registers as being unavailable for reuse.
5291 */
5295 }
5297 /*
5298 ** Validate that no temporary register falls within the range of
5299 ** iFirst..iLast, inclusive. This routine is only call from within assert()
5300 ** statements.
5301 */
5302 #ifdef SQLITE_DEBUG
5308 ){
5310 }
5314 }
5315 }
5317 }