*** ./src/backend/parser/gram.old.y	Wed Mar  3 15:03:27 1999
--- ./src/backend/parser/gram.y	Wed Dec  2 12:54:12 1998
***************
*** 3323,3328 ****
--- 3323,3330 ----
  				{	$$ = makeA_Expr(OP, "<", $1, $3); }
  		| a_expr '>' a_expr
  				{	$$ = makeA_Expr(OP, ">", $1, $3); }
+   		| a_expr '=' NULL_P
+   				{	$$ = makeA_Expr(ISNULL, NULL, $1, NULL); }
  		| a_expr '=' a_expr
  				{	$$ = makeA_Expr(OP, "=", $1, $3); }
  		| ':' a_expr