MDEV-15899 Server crashes in st_join_table::is_inner_table_of_outer_join

The crash happened because JOIN::check_for_splittable_materialized()
called by mistake the function JOIN_TAB::is_inner_table_of_outer_join()
instead of the function TABLE_LIST::is_inner_table_of_outer_join().
The former cannot be called before the call of make_outerjoin_info().

mysql-test/main/derived_cond_pushdown.result

@@ -15119,3 +15119,49 @@ Warnings:
 Note	1003	/* select#1 */ select NULL AS `f`,`v2`.`f` AS `f` from `test`.`t1` `a` straight_join `test`.`t1` `b` join `test`.`v2` where 0
 DROP VIEW v1,v2;
 DROP TABLE t1;
+#
+# MDEV-15899: derived with WF without any key access
+#
+create table t1 (f1 int, f2 int, f4 int);
+insert into t1 values
+(3,1,1), (3,0,9), (0,1,8), (9,0,0), (3,0,9);
+with
+cte as (select  median(f2) over (partition by f1) as k1 from t1 order by f1),
+cte1 as (select median(f4) over (partition by f1) as k2 from t1)
+select k1,k2 from cte1, cte;
+k1	k2
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+1.0000000000	8.0000000000
+1.0000000000	8.0000000000
+1.0000000000	8.0000000000
+1.0000000000	8.0000000000
+1.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+0.0000000000	8.0000000000
+explain with
+cte as (select  median(f2) over (partition by f1) as k1 from t1 order by f1),
+cte1 as (select median(f4) over (partition by f1) as k2 from t1)
+select k1,k2 from cte1, cte;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	5	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	5	Using join buffer (flat, BNL join)
+3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	Using temporary
+drop table t1;

mysql-test/main/derived_cond_pushdown.test

@@ -2671,3 +2671,22 @@ SELECT * FROM v1 JOIN v2 ON v1.f = v2.f;
 
 DROP VIEW v1,v2;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-15899: derived with WF without any key access
+--echo #
+
+create table t1 (f1 int, f2 int, f4 int);
+insert into t1 values
+  (3,1,1), (3,0,9), (0,1,8), (9,0,0), (3,0,9);
+
+let $q=
+with
+cte as (select  median(f2) over (partition by f1) as k1 from t1 order by f1),
+cte1 as (select median(f4) over (partition by f1) as k2 from t1)
+select k1,k2 from cte1, cte;
+
+eval $q;
+eval explain $q;
+
+drop table t1;

sql/opt_split.cc

@@ -352,8 +352,9 @@ bool JOIN::check_for_splittable_materialized()
 
     Field *ord_field= ((Item_field *) (ord_item->real_item()))->field;
 
-    JOIN_TAB *tab= ord_field->table->reginfo.join_tab;
-    if (tab->is_inner_table_of_outer_join())
+    /* Ignore fields from  of inner tables of outer joins */
+    TABLE_LIST *tbl= ord_field->table->pos_in_table_list;
+    if (tbl->is_inner_table_of_outer_join())
       continue;
 
     List_iterator<Item> li(fields_list);