Ensure the functions that appear to be constant are not factored out of

expression that originate on the right-hand side of a LEFT JOIN.
Ticket [6710d2f7a13a2997]

FossilOrigin-Name: 500c9152daaf11cf69d778aa8592175f6088337c6667c59af6df3a24cd81eb0e

1 files changed, 13 insertions, 0 deletions

diff --git a/src/expr.c b/src/expr.c
index 8f02ae569..ef4221ff8 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -3994,10 +3994,23 @@ expr_code_doover:
       break;
     }
 
+    /* TK_IF_NULL_ROW Expr nodes are inserted ahead of expressions
+    ** that derive from the right-hand table of a LEFT JOIN.  The
+    ** Expr.iTable value is the table number for the right-hand table.
+    ** The expression is only evaluated if that table is not currently
+    ** on a LEFT JOIN NULL row.
+    */
     case TK_IF_NULL_ROW: {
       int addrINR;
+      u8 okConstFactor = pParse->okConstFactor;
       addrINR = sqlite3VdbeAddOp1(v, OP_IfNullRow, pExpr->iTable);
+      /* Temporarily disable factoring of constant expressions, since
+      ** even though expressions may appear to be constant, they are not
+      ** really constant because they originate from the right-hand side
+      ** of a LEFT JOIN. */
+      pParse->okConstFactor = 0;
       inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
+      pParse->okConstFactor = okConstFactor;
       sqlite3VdbeJumpHere(v, addrINR);
       sqlite3VdbeChangeP3(v, addrINR, inReg);
       break;