Merge olga.mysql.com:/home/igor/mysql-5.0-opt

into  olga.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug28571

mysql-test/r/join_outer.result

@@ -1239,3 +1239,18 @@ Handler_read_prev	0
 Handler_read_rnd	0
 Handler_read_rnd_next	6
 DROP TABLE t1,t2;
+CREATE TABLE t1 (c int  PRIMARY KEY, e int NOT NULL);
+INSERT INTO t1 VALUES (1,0), (2,1);
+CREATE TABLE t2 (d int PRIMARY KEY);
+INSERT INTO t2 VALUES (1), (2), (3);
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
+1	SIMPLE	t2	index	NULL	PRIMARY	4	NULL	3	Using where; Using index; Not exists
+SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
+c	e	d
+1	0	NULL
+SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL;
+c	e	d
+1	0	NULL
+DROP TABLE t1,t2;

mysql-test/t/join_outer.test

@@ -845,3 +845,19 @@ SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL;
 show status like 'Handler_read%';
 
 DROP TABLE t1,t2;
+
+#
+# Bug 28571: outer join with false on condition over constant tables 
+#
+
+CREATE TABLE t1 (c int  PRIMARY KEY, e int NOT NULL);
+INSERT INTO t1 VALUES (1,0), (2,1);
+CREATE TABLE t2 (d int PRIMARY KEY);
+INSERT INTO t2 VALUES (1), (2), (3);
+
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
+SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d IS NULL;
+SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL;
+
+DROP TABLE t1,t2;
+

sql/sql_select.cc

@@ -5666,28 +5666,6 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
                               join->const_table_map,
                               (table_map) 0);
         DBUG_EXECUTE("where",print_where(const_cond,"constants"););
-        for (JOIN_TAB *tab= join->join_tab+join->const_tables;
-             tab < join->join_tab+join->tables ; tab++)
-        {
-          if (*tab->on_expr_ref)
-          {
-            JOIN_TAB *cond_tab= tab->first_inner;
-            COND *tmp= make_cond_for_table(*tab->on_expr_ref,
-                                           join->const_table_map,
-                                         (  table_map) 0);
-            if (!tmp)
-              continue;
-            tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
-            if (!tmp)
-              DBUG_RETURN(1);
-            tmp->quick_fix_field();
-            cond_tab->select_cond= !cond_tab->select_cond ? tmp :
-	                            new Item_cond_and(cond_tab->select_cond,tmp);
-            if (!cond_tab->select_cond)
-	      DBUG_RETURN(1);
-            cond_tab->select_cond->quick_fix_field();
-          }       
-        }
         if (const_cond && !const_cond->val_int())
         {
 	  DBUG_PRINT("info",("Found impossible WHERE condition"));
@@ -5918,13 +5896,39 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
       }
       
       /* 
-        Push down all predicates from on expressions.
-        Each of these predicated are guarded by a variable
+        Push down conditions from all on expressions.
+        Each of these conditions are guarded by a variable
         that turns if off just before null complemented row for
-        outer joins is formed. Thus, the predicates from an
+        outer joins is formed. Thus, the condition from an
         'on expression' are guaranteed not to be checked for
         the null complemented row.
       */ 
+
+      /* First push down constant conditions from on expressions */
+      for (JOIN_TAB *tab= join->join_tab+join->const_tables;
+           tab < join->join_tab+join->tables ; tab++)
+      {
+        if (*tab->on_expr_ref)
+        {
+          JOIN_TAB *cond_tab= tab->first_inner;
+          COND *tmp= make_cond_for_table(*tab->on_expr_ref,
+                                         join->const_table_map,
+                                         (table_map) 0);
+          if (!tmp)
+            continue;
+          tmp= new Item_func_trig_cond(tmp, &cond_tab->not_null_compl);
+          if (!tmp)
+            DBUG_RETURN(1);
+          tmp->quick_fix_field();
+          cond_tab->select_cond= !cond_tab->select_cond ? tmp :
+	                            new Item_cond_and(cond_tab->select_cond,tmp);
+          if (!cond_tab->select_cond)
+	    DBUG_RETURN(1);
+          cond_tab->select_cond->quick_fix_field();
+        }       
+      }
+
+      /* Push down non-constant conditions from on expressions */
       JOIN_TAB *last_tab= tab;
       while (first_inner_tab && first_inner_tab->last_inner == last_tab)
       {