merged

mysql-test/r/group_by.result

@@ -758,6 +758,15 @@ select date(left(f1+0,8)) from t1 group by 1;
 date(left(f1+0,8))
 2005-06-06
 drop table t1;
+create table t1(f1 varchar(5) key);
+insert into t1 values (1),(2);
+select sql_buffer_result max(f1) is null from t1;
+max(f1) is null
+0
+select sql_buffer_result max(f1)+1 from t1;
+max(f1)+1
+3
+drop table t1;
 CREATE TABLE t1 (n int);
 INSERT INTO t1 VALUES (1);
 SELECT n+1 AS n FROM t1 GROUP BY n;

mysql-test/t/group_by.test

@@ -602,6 +602,16 @@ SELECT n+1 AS n FROM t1 GROUP BY n;
 --enable_ps_protocol
 DROP TABLE t1;
 
+#
+# BUG#12695: Item_func_isnull::update_used_tables
+# did not update const_item_cache
+#
+create table t1(f1 varchar(5) key);
+insert into t1 values (1),(2);
+select sql_buffer_result max(f1) is null from t1;
+select sql_buffer_result max(f1)+1 from t1;
+drop table t1;
+
 # End of 4.1 tests
 
 #

sql/item_cmpfunc.h

@@ -910,7 +910,7 @@ public:
     else
     {
       args[0]->update_used_tables();
-      if (!(used_tables_cache=args[0]->used_tables()))
+      if ((const_item_cache= !(used_tables_cache= args[0]->used_tables())))
       {
 	/* Remember if the value is always NULL or never NULL */
 	cached_value= (longlong) args[0]->is_null();