1 files changed, 55 insertions, 1 deletions

diff --git a/src/expr.c b/src/expr.c
index bceb5efb0..30f9031e2 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4043,6 +4043,46 @@ static int exprCodeInlineFunction(
   return target;
 }
 
+/*
+** Check to see if pExpr is one of the indexed expressions on pParse->pIdxExpr.
+** If it is, then resolve the expression by reading from the index and
+** return the register into which the value has been read.  If pExpr is
+** not an indexed expression, then return negative.
+*/
+static SQLITE_NOINLINE int sqlite3IndexedExprLookup(
+  Parse *pParse,   /* The parsing context */
+  Expr *pExpr,     /* The expression to potentially bypass */
+  int target       /* Where to store the result of the expression */
+){
+  IndexedExpr *p;
+  Vdbe *v;
+  for(p=pParse->pIdxExpr; p; p=p->pIENext){
+    if( p->iDataCur<0 ) continue;
+    if( sqlite3ExprCompare(0, pExpr, p->pExpr, p->iDataCur)!=0 ) continue;
+    v = pParse->pVdbe;
+    assert( v!=0 );
+    if( p->bMaybeNullRow ){
+      /* If the index is on a NULL row due to an outer join, then we
+      ** cannot extract the value from the index.  The value must be
+      ** computed using the original expression. */
+      int addr = sqlite3VdbeCurrentAddr(v);
+      sqlite3VdbeAddOp3(v, OP_IfNullRow, p->iIdxCur, addr+3, target);
+      VdbeCoverage(v);
+      sqlite3VdbeAddOp3(v, OP_Column, p->iIdxCur, p->iIdxCol, target);
+      sqlite3VdbeGoto(v, 0);
+      p = pParse->pIdxExpr;
+      pParse->pIdxExpr = 0;
+      sqlite3ExprCode(pParse, pExpr, target);
+      pParse->pIdxExpr = p;
+      sqlite3VdbeJumpHere(v, addr+2);
+    }else{
+      sqlite3VdbeAddOp3(v, OP_Column, p->iIdxCur, p->iIdxCol, target);
+    }
+    return target;
+  }
+  return -1;  /* Not found */
+}
+
 
 /*
 ** Generate code into the current Vdbe to evaluate the given
@@ -4068,6 +4108,14 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
   assert( target>0 && target<=pParse->nMem );
   assert( v!=0 );
 
+  if( pParse->pIdxExpr!=0 
+   && pExpr!=0
+   && !ExprHasProperty(pExpr, EP_Leaf)
+   && (r1 = sqlite3IndexedExprLookup(pParse, pExpr, target))>=0
+  ){
+    return r1;
+  }
+
 expr_code_doover:
   if( pExpr==0 ){
     op = TK_NULL;
@@ -5570,7 +5618,13 @@ int sqlite3ExprCompare(
     if( pB->op==TK_COLLATE && sqlite3ExprCompare(pParse, pA,pB->pLeft,iTab)<2 ){
       return 1;
     }
-    return 2;
+    if( pA->op==TK_AGG_COLUMN && pB->op==TK_COLUMN 
+     && pB->iTable<0 && pA->iTable==iTab
+    ){
+      /* fall through */
+    }else{
+      return 2;
+    }
   }
   assert( !ExprHasProperty(pA, EP_IntValue) );
   assert( !ExprHasProperty(pB, EP_IntValue) );