Change the way "(a, b) = (SELECT *)" expressions are handled in where.c if there is an index on one of the columns only.

FossilOrigin-Name: 4dfebff2924f46284d5b9cda69175f79b29d6028

4 files changed, 31 insertions, 20 deletions

diff --git a/src/expr.c b/src/expr.c
index 2921898d3..3dcb73ff1 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -3512,18 +3512,6 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       break;
     }
 
-    case TK_SELECT_COLUMN: {
-      Expr *pLeft = pExpr->pLeft;
-      assert( pLeft );
-      assert( pLeft->op==TK_SELECT || pLeft->op==TK_REGISTER );
-      if( pLeft->op==TK_SELECT ){
-        pLeft->iTable = sqlite3CodeSubselect(pParse, pLeft, 0, 0);
-        pLeft->op = TK_REGISTER;
-      }
-      inReg = pLeft->iTable + pExpr->iColumn;
-      break;
-    }
-
     /*
     ** Form A:
     **   CASE x WHEN e1 THEN r1 WHEN e2 THEN r2 ... WHEN eN THEN rN ELSE y END
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index ea41e6575..9dfc0bcaa 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3936,7 +3936,8 @@ void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
 int sqlite3GetToken(const unsigned char *, int *);
 void sqlite3NestedParse(Parse*, const char*, ...);
 void sqlite3ExpirePreparedStatements(sqlite3*);
-int sqlite3CodeSubselect(Parse *, Expr *, int, int);
+int sqlite3CodeSubselect(Parse*, Expr *, int, int);
+int sqlite3ExprCheckIN(Parse*, Expr*);
 void sqlite3SelectPrep(Parse*, Select*, NameContext*);
 void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p);
 int sqlite3MatchSpanName(const char*, const char*, const char*, const char*);
diff --git a/src/wherecode.c b/src/wherecode.c
index 892831d82..9db4a0146 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -359,7 +359,31 @@ static int codeEqualityTerm(
   assert( pLevel->pWLoop->aLTerm[iEq]==pTerm );
   assert( iTarget>0 );
   if( pX->op==TK_EQ || pX->op==TK_IS ){
-    iReg = sqlite3ExprCodeTarget(pParse, pX->pRight, iTarget);
+    Expr *pRight = pX->pRight;
+    if( pRight->op==TK_SELECT_COLUMN ){
+      /* This case occurs for expressions like "(a, b) == (SELECT ...)". */
+      WhereLoop *pLoop = pLevel->pWLoop;
+      int i;
+      Expr *pSub = pRight->pLeft;
+      assert( pSub->op==TK_SELECT );
+      for(i=pLoop->nSkip; i<iEq; i++){
+        Expr *pExpr = pLoop->aLTerm[i]->pExpr->pRight;
+        if( pExpr && pExpr->op==TK_SELECT_COLUMN && pExpr->pLeft==pSub ) break;
+      }
+
+      if( i==iEq ){
+        iReg = sqlite3CodeSubselect(pParse, pSub, 0, 0);
+        for(/*no-op*/; i<pLoop->nLTerm; i++){
+          Expr *pExpr = pLoop->aLTerm[i]->pExpr->pRight;
+          if( pExpr && pExpr->op==TK_SELECT_COLUMN && pExpr->pLeft==pSub ){
+            sqlite3VdbeAddOp2(v, OP_Copy, iReg+pExpr->iColumn, iTarget-iEq+i);
+          }
+        }
+      }
+      iReg = iTarget;
+    }else{
+      iReg = sqlite3ExprCodeTarget(pParse, pRight, iTarget);
+    }
   }else if( pX->op==TK_ISNULL ){
     iReg = iTarget;
     sqlite3VdbeAddOp2(v, OP_Null, 0, iReg);
@@ -1489,10 +1513,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
     }
 
-    /* Disable the start and end range terms if possible */
-    /* disableTerm(pLevel, pRangeStart); */
-    /* disableTerm(pLevel, pRangeEnd); */
-
     /* Seek the table cursor, if required */
     if( omitTable ){
       /* pIdx is a covering index.  No need to access the main table. */
@@ -1594,7 +1614,7 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     u16 wctrlFlags;                    /* Flags for sub-WHERE clause */
     Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
     Table *pTab = pTabItem->pTab;
-   
+
     pTerm = pLoop->aLTerm[0];
     assert( pTerm!=0 );
     assert( pTerm->eOperator & WO_OR );
diff --git a/src/whereexpr.c b/src/whereexpr.c
index 9c9be9903..4b96e2faa 100644
--- a/src/whereexpr.c
+++ b/src/whereexpr.c
@@ -962,7 +962,8 @@ static void exprAnalyze(
     Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight);
     u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV;
 
-    if( op==TK_IN && pTerm->iField>0 ){
+    if( pTerm->iField>0 ){
+      assert( op==TK_IN );
       assert( pLeft->op==TK_VECTOR );
       pLeft = pLeft->x.pList->a[pTerm->iField-1].pExpr;
     }
@@ -979,6 +980,7 @@ static void exprAnalyze(
       WhereTerm *pNew;
       Expr *pDup;
       u16 eExtraOp = 0;        /* Extra bits for pNew->eOperator */
+      assert( pTerm->iField==0 );
       if( pTerm->leftCursor>=0 ){
         int idxNew;
         pDup = sqlite3ExprDup(db, pExpr, 0);