Fix: Operand Order Affects OR.

	where x <> 1 or x isnull
didn't return tuples with x NULL.

diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c
index 2f351276d4bf2ea99bc0bda7a6961390e8698595..4d96bdb0ada0f7a10b610b4927d458b99e2bff50 100644 (file)
--- a/src/backend/executor/execQual.c
+++ b/src/backend/executor/execQual.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.17 1997/09/12 04:07:36 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.18 1997/09/22 04:19:36 vadim Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1044,7 +1044,22 @@ ExecEvalOr(Expr *orExpr, ExprContext *econtext, bool *isNull)
         * ----------------
         */
        if (*isNull)
+       {
            IsNull = *isNull;
+           /*
+            * Many functions don't (or can't!) check is an argument
+            * NULL or NOT_NULL and may return TRUE (1) with *isNull TRUE
+            * (an_int4_column <> 1: int4ne returns TRUE for NULLs).
+            * Not having time to fix function manager I want to fix
+            * OR: if we had 'x <> 1 OR x isnull' then TRUE, TRUE were
+            * returned by 'x <> 1' for NULL ... but ExecQualClause say
+            * that qualification *fails* if isnull is TRUE for all values
+            * returned by ExecEvalExpr. So, force this rule here: if isnull 
+            * is TRUE then clause failed. Note: nullvalue() & nonnullvalue() 
+            * always set isnull to FALSE for NULLs.    - vadim 09/22/97
+            */
+           const_value = 0;
+       }
 
        /* ----------------
         *   if we have a true result, then we return it.