Add restriction (9) to the push-down optimization: If the subquery is

a compound then all arms of the compound must have the same affinity.
dbsqlfuzz 3a548de406a50e896c1bf7142692d35d339d697f.

FossilOrigin-Name: 1ad41840c5e0fa702ba2c0df77a3ea126bd695b910b5d1271fa3129c38c58f5f

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\stest\scase\sin\sfts3expr4.test\sto\saccount\sfor\sdifferent\slocales.
-D 2022-11-24T17:58:55.503
+C Add\srestriction\s(9)\sto\sthe\spush-down\soptimization:\s\sIf\sthe\ssubquery\sis\na\scompound\sthen\sall\sarms\sof\sthe\scompound\smust\shave\sthe\ssame\saffinity.\ndbsqlfuzz\s3a548de406a50e896c1bf7142692d35d339d697f.
+D 2022-11-25T15:52:00.241
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -641,7 +641,7 @@ F src/printf.c e99ee9741e79ae3873458146f59644276657340385ade4e76a5f5d1c25793764
 F src/random.c 606b00941a1d7dd09c381d3279a058d771f406c5213c9932bbd93d5587be4b9c
 F src/resolve.c efea4e5fbecfd6d0a9071b0be0d952620991673391b6ffaaf4c277b0bb674633
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c 4c48373abb4e67129c36bc15d1f5a99a0dfd9534afeb539a2169a09ae91ccec9
+F src/select.c bafe6424e942aad558b2d4be8dbcf5e35ce427ce3cf66d7f0c0ac37c366b00c6
 F src/shell.c.in 09cb15d7421c475f2d308f6a4312d8d690916ea5cb62ea1618f2f4ce5703af35
 F src/sqlite.h.in 100fc660c2f19961b8ed8437b9d53d687de2f8eb2b96437ec6da216adcb643ca
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -1403,7 +1403,7 @@ F test/printf.test 390d0d7fcffc3c4ea3c1bb4cbb267444e32b33b048ae21895f23a291844fe
 F test/printf2.test 3f55c1871a5a65507416076f6eb97e738d5210aeda7595a74ee895f2224cce60
 F test/progress.test ebab27f670bd0d4eb9d20d49cef96e68141d92fb
 F test/ptrchng.test ef1aa72d6cf35a2bbd0869a649b744e9d84977fc
-F test/pushdown.test 5e72c51c5e33253ed639ccee1e01ce62d62b6eee5ca893cd82334e4ee7b1d7fc
+F test/pushdown.test c69f0970ea17e0afc674b89741f60c172cb6f761d81665fc71015f674f0f66ba
 F test/queryonly.test 5f653159e0f552f0552d43259890c1089391dcca
 F test/quick.test 1681febc928d686362d50057c642f77a02c62e57
 F test/quota-glob.test 32901e9eed6705d68ca3faee2a06b73b57cb3c26
@@ -2059,8 +2059,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 18e89a436daa18a8c972caf06b298da43c97a6ea3e2e5229dccb6920c27bfdb9
-R e3089d3062e617db155d3fe3a44f9c32
-U dan
-Z c38105809dd01fc34e6f6bf40716c164
+P a2b6883ac2ef878f525ee847b170beb9f9ab9d1fa67557101be2cdae1e7f7a57
+R 9c0acbc69bb427be679e111e4ec839ec
+U drh
+Z ae1fb8eb841aaf444344209ddd2c7ea7
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-a2b6883ac2ef878f525ee847b170beb9f9ab9d1fa67557101be2cdae1e7f7a57
+1ad41840c5e0fa702ba2c0df77a3ea126bd695b910b5d1271fa3129c38c58f5f

src/select.c

@@ -4050,6 +4050,34 @@ static ExprList *findLeftmostExprlist(Select *pSel){
   return pSel->pEList;
 }
 
+/*
+** Return true if any of the result-set columns in the compound query
+** have incompatible affinities on one or more arms of the compound.
+*/
+static int compoundHasDifferentAffinities(Select *p){
+  int ii;
+  ExprList *pList;
+  assert( p!=0 );
+  assert( p->pEList!=0 );
+  assert( p->pPrior!=0 );
+  pList = p->pEList;
+  for(ii=0; ii<pList->nExpr; ii++){
+    char aff;
+    Select *pSub1;
+    assert( pList->a[ii].pExpr!=0 );
+    aff = sqlite3ExprAffinity(pList->a[ii].pExpr);
+    for(pSub1=p->pPrior; pSub1; pSub1=pSub1->pPrior){
+      assert( pSub1->pEList!=0 );
+      assert( pSub1->pEList->nExpr>ii );
+      assert( pSub1->pEList->a[ii].pExpr!=0 );
+      if( sqlite3ExprAffinity(pSub1->pEList->a[ii].pExpr)!=aff ){
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
 /*
 ** This routine attempts to flatten subqueries as a performance optimization.
@@ -4153,7 +4181,8 @@ static ExprList *findLeftmostExprlist(Select *pSel){
 **              query or there are no RIGHT or FULL JOINs in any arm
 **              of the subquery.  (This is a duplicate of condition (27b).)
 **        (17h) The corresponding result set expressions in all arms of the
-**              compound must have the same affinity.
+**              compound must have the same affinity. (See restriction (9)
+**              on the push-down optimization.)
 **
 **        The parent and sub-query may contain WHERE clauses. Subject to
 **        rules (11), (13) and (14), they may also contain ORDER BY,
@@ -4372,19 +4401,7 @@ static int flattenSubquery(
     if( (p->selFlags & SF_Recursive) ) return 0;
 
     /* Restriction (17h) */
-    for(ii=0; ii<pSub->pEList->nExpr; ii++){
-      char aff;
-      assert( pSub->pEList->a[ii].pExpr!=0 );
-      aff = sqlite3ExprAffinity(pSub->pEList->a[ii].pExpr);
-      for(pSub1=pSub->pPrior; pSub1; pSub1=pSub1->pPrior){
-        assert( pSub1->pEList!=0 );
-        assert( pSub1->pEList->nExpr>ii );
-        assert( pSub1->pEList->a[ii].pExpr!=0 );
-        if( sqlite3ExprAffinity(pSub1->pEList->a[ii].pExpr)!=aff ){
-          return 0;
-        }
-      }
-    }
+    if( compoundHasDifferentAffinities(pSub) ) return 0;
 
     if( pSrc->nSrc>1 ){
       if( pParse->nSelect>500 ) return 0;
@@ -5036,6 +5053,11 @@ static int pushDownWindowCheck(Parse *pParse, Select *pSubq, Expr *pExpr){
 **       But it is a lot of work to check that case for an obscure and
 **       minor optimization, so we omit it for now.)
 **
+**   (9) If the subquery is a compound, then all arms of the compound must
+**       have the same affinity.  (This is the same as restriction (17h)
+**       for query flattening.)
+**       
+**
 ** Return 0 if no changes are made and non-zero if one or more WHERE clause
 ** terms are duplicated into the subquery.
 */
@@ -5061,6 +5083,9 @@ static int pushDownWhereTerms(
       if( op!=TK_ALL && op!=TK_SELECT ) return 0;  /* restriction (8) */
       if( pSel->pWin ) return 0;    /* restriction (6b) */
     }
+    if( compoundHasDifferentAffinities(pSubq) ){
+      return 0;  /* restriction (9) */
+    }
   }else{
     if( pSubq->pWin && pSubq->pWin->pPartition==0 ) return 0;
   }

test/pushdown.test

@@ -86,6 +86,31 @@ do_test 2.2 {
   set L
 } {three}
 
-
+# 2022-11-25 dbsqlfuzz crash-3a548de406a50e896c1bf7142692d35d339d697f
+# Disable the push-down optimization for compound subqueries if any
+# arm of the compound has an incompatible affinity.
+#
+reset_db
+do_execsql_test 3.1 {
+  CREATE TABLE t0(c0 INT);
+  INSERT INTO t0 VALUES(0);
+  CREATE TABLE t1_a(a INTEGER PRIMARY KEY, b TEXT);
+  INSERT INTO t1_a VALUES(1,'one'); --,(4,'four');
+  CREATE TABLE t1_b(c INTEGER PRIMARY KEY, d TEXT);
+  INSERT INTO t1_b VALUES(2,'two'); --,(5,'five');
+  CREATE VIEW v0 AS SELECT CAST(t0.c0 AS INTEGER) AS c0 FROM t0;
+  CREATE VIEW t1 AS SELECT a, b FROM t1_a UNION ALL SELECT c, 0 FROM t1_b;
+  SELECT t1.a, quote(t1.b), t0.c0 AS cd FROM t0 LEFT JOIN v0 ON v0.c0!=0,t1;
+} {
+  1 'one' 0
+  2 '0'   0
+}
+do_execsql_test 3.2 {
+  SELECT a, quote(b), cd FROM (
+    SELECT t1.a, t1.b, t0.c0 AS cd FROM t0 LEFT JOIN v0 ON v0.c0!=0,t1
+  ) WHERE a=2 AND b='0' AND cd=0;
+} {
+  2 '0'   0
+}
   
 finish_test