MDEV-14346: incorrect result of intersect with ANY/ALL/IN subquery

Reinit internal state of select_unit before using to correctly run it after first time.

mysql-test/r/intersect.result

@@ -689,4 +689,17 @@ View	Create View	character_set_client	collation_connection
 v1	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS (select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1`) union select `__3`.`c` AS `c`,`__3`.`d` AS `d` from ((select `test`.`t2`.`c` AS `c`,`test`.`t2`.`d` AS `d` from `test`.`t2`) intersect (select `test`.`t3`.`e` AS `e`,`test`.`t3`.`f` AS `f` from `test`.`t3`)) `__3` union (select 4 AS `4`,4 AS `4`)	latin1	latin1_swedish_ci
 drop view v1;
 drop tables t1,t2,t3;
+#
+# MDEV-14346:incorrect result of intersect with ANY/ALL/IN subquery
+#
+CREATE TABLE t (i INT);
+INSERT INTO t VALUES (1),(2);
+SELECT * FROM t WHERE i != ANY ( SELECT 6 INTERSECT SELECT 3 );
+i
+select i from t where
+exists ((select 6 as r from dual having t.i <> 6)
+intersect
+(select 3 from dual having t.i <> 3));
+i
+drop table t;
 # End of 10.3 tests

mysql-test/t/intersect.test

@@ -190,4 +190,19 @@ show create view v1;
 drop view v1;
 drop tables t1,t2,t3;
 
+--echo #
+--echo # MDEV-14346:incorrect result of intersect with ANY/ALL/IN subquery
+--echo #
+CREATE TABLE t (i INT);
+INSERT INTO t VALUES (1),(2);
+SELECT * FROM t WHERE i != ANY ( SELECT 6 INTERSECT SELECT 3 );
+
+select i from t where
+   exists ((select 6 as r from dual having t.i <> 6)
+           intersect
+           (select 3 from dual having t.i <> 3));
+
+drop table t;
+
+
 --echo # End of 10.3 tests

sql/sql_class.h

@@ -5103,10 +5103,11 @@ class select_unit :public select_result_interceptor
 
   select_unit(THD *thd_arg):
     select_result_interceptor(thd_arg),
-    curr_step(0), prev_step(0), curr_sel(UINT_MAX),
-    step(UNION_TYPE), intersect_mark(0), write_err(0), table(0),
-    records(0)
-  { tmp_table_param.init(); }
+    intersect_mark(0), table(0)
+  {
+    init();
+    tmp_table_param.init();
+  }
   int prepare(List<Item> &list, SELECT_LEX_UNIT *u);
   /**
     Do prepare() and prepare2() if they have been postponed until
@@ -5130,6 +5131,14 @@ class select_unit :public select_result_interceptor
                                    bool keep_row_order,
                                    uint hidden);
   TMP_TABLE_PARAM *get_tmp_table_param() { return &tmp_table_param; }
+  void init()
+  {
+    curr_step= prev_step= 0;
+    curr_sel= UINT_MAX;
+    step= UNION_TYPE;
+    write_err= 0;
+    records= 0;
+  }
   void change_select();
 };
 

sql/sql_union.cc

@@ -1384,6 +1384,9 @@ bool st_select_lex_unit::exec()
   if (saved_error)
     DBUG_RETURN(saved_error);
 
+  if (union_result)
+    union_result->init();
+
   if (uncacheable || !item || !item->assigned() || describe)
   {
     if (!fake_select_lex && !(with_element && with_element->is_recursive))