From 33dfd07b96aabed6b928d226d0be3237da3b5e0f Mon Sep 17 00:00:00 2001
From: ygrek <ygrek@autistici.org>
Date: Tue, 17 Apr 2018 17:16:32 +0300
Subject: [PATCH] sql: improve single-row detection (fix #47)

---
 lib/syntax.ml         | 17 +++++++++++------
 test/misc.sql         |  3 +++
 test/out/function.xml |  2 +-
 test/out/misc.xml     | 10 ++++++++--
 4 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/lib/syntax.ml b/lib/syntax.ml
index fa9230f..12ceb39 100644
--- a/lib/syntax.ml
+++ b/lib/syntax.ml
@@ -38,13 +38,18 @@ let get_params_q e =
   in
   loop [] e |> List.rev
 
+let rec is_singular = function
+| Value _
+| Param _ -> true
+| Column _ -> false
+| Fun (func,args) ->
+  (* grouping function of zero or single parameter or function of all singular values *)
+  (Type.is_grouping func && List.length args <= 1) || List.for_all is_singular args
+| Select _ -> false (* ? *)
+| Inserted _ -> false (* ? *)
+
 let test_all_grouping columns =
-  let test = function
-  (* grouping function of zero or single parameter *)
-  | Expr (Fun (func,args),_) when Type.is_grouping func && List.length args <= 1 -> true
-  | _ -> false
-  in
-  List.for_all test columns
+  List.for_all (function Expr (e,_) -> is_singular e | All | AllOf _ -> false) columns
 
 let cross = List.fold_left Schema.cross []
 
diff --git a/test/misc.sql b/test/misc.sql
index eec33a7..79576ab 100644
--- a/test/misc.sql
+++ b/test/misc.sql
@@ -46,3 +46,6 @@ INSERT INTO test VALUES
 (1, 'one'),
 (2, 'two'),
 (3, 'three');
+
+-- @issue47
+SELECT count(*) > 0 FROM test;
diff --git a/test/out/function.xml b/test/out/function.xml
index bdabad2..f0e135a 100644
--- a/test/out/function.xml
+++ b/test/out/function.xml
@@ -5,7 +5,7 @@
   <in/>
   <out/>
  </stmt>
- <stmt name="select_1" sql="SELECT increment(2)" kind="select" cardinality="0,1">
+ <stmt name="select_1" sql="SELECT increment(2)" kind="select" cardinality="1">
   <in/>
   <out>
    <value name="_0" type="Int"/>
diff --git a/test/out/misc.xml b/test/out/misc.xml
index 63f9771..a184853 100644
--- a/test/out/misc.xml
+++ b/test/out/misc.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 
 <sqlgg>
- <stmt name="select_0" sql="SELECT strftime('%s','now')" kind="select" cardinality="0,1">
+ <stmt name="select_0" sql="SELECT strftime('%s','now')" kind="select" cardinality="1">
   <in/>
   <out>
    <value name="_0" type="Text"/>
@@ -108,7 +108,7 @@
   <in/>
   <out/>
  </stmt>
- <stmt name="select_19" sql="SELECT $function$&#x0A;BEGIN&#x0A;    RETURN ($1 ~ $q$[\t\r\n\v\\]$q$);&#x0A;END;&#x0A;$function$" kind="select" cardinality="0,1">
+ <stmt name="select_19" sql="SELECT $function$&#x0A;BEGIN&#x0A;    RETURN ($1 ~ $q$[\t\r\n\v\\]$q$);&#x0A;END;&#x0A;$function$" kind="select" cardinality="1">
   <in/>
   <out>
    <value name="_0" type="Text"/>
@@ -122,4 +122,10 @@
   <in/>
   <out/>
  </stmt>
+ <stmt name="issue47" sql="SELECT count(*) &gt; 0 FROM test" kind="select" cardinality="1">
+  <in/>
+  <out>
+   <value name="_0" type="Bool"/>
+  </out>
+ </stmt>
 </sqlgg>
-- 
2.11.4.GIT