diff --git a/mysql-test/suite/compat/oracle/r/ora_outer_join.result b/mysql-test/suite/compat/oracle/r/ora_outer_join.result
index 13a71cd03e5..c8e22b3e176 100644
--- a/mysql-test/suite/compat/oracle/r/ora_outer_join.result
+++ b/mysql-test/suite/compat/oracle/r/ora_outer_join.result
@@ -649,3 +649,39 @@ ERROR 42000: You have an error in your SQL syntax; check the manual that corresp
 set SQL_MODE= oracle;
 drop view v1;
 drop table t1,t2;
+#
+# MDEV-36830: Oracle outer join syntax (+): outer join not converted to inner
+#
+create table t1 (
+a int not null,
+b int not null
+);
+insert into t1 select seq,seq from seq_1_to_10;
+create table t2 (
+a int not null,
+b int not null
+);
+insert into t2 select seq,seq from seq_1_to_3;
+# Must be converted to inner join:
+explain extended
+select * from t1, t2
+where
+t1.a=1 and
+t1.b=t2.b(+) and
+t2.b=1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	100.00	Using where
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
+Warnings:
+Note	1003	select "test"."t1"."a" AS "a","test"."t1"."b" AS "b","test"."t2"."a" AS "a","test"."t2"."b" AS "b" from "test"."t1" left join "test"."t2" on("test"."t1"."b" = 1) where "test"."t1"."a" = 1 and "test"."t2"."b" = 1
+drop table t1,t2;
+#
+# MDEV-36838: Oracle outer join syntax (+): server crash on derived tables
+#
+select a.a
+from (select 1 as a) a,
+(select 2 as b) b
+where a.a=b.b(+);
+a
+1
+# End of 12.0 tests
diff --git a/mysql-test/suite/compat/oracle/t/ora_outer_join.test b/mysql-test/suite/compat/oracle/t/ora_outer_join.test
index 27783a9681b..e4a9f102405 100644
--- a/mysql-test/suite/compat/oracle/t/ora_outer_join.test
+++ b/mysql-test/suite/compat/oracle/t/ora_outer_join.test
@@ -436,3 +436,42 @@ set SQL_MODE= oracle;
 
 drop view v1;
 drop table t1,t2;
+
+--echo #
+--echo # MDEV-36830: Oracle outer join syntax (+): outer join not converted to inner
+--echo #
+--source include/have_sequence.inc
+
+create table t1 (
+  a int not null,
+  b int not null
+);
+insert into t1 select seq,seq from seq_1_to_10;
+
+create table t2 (
+  a int not null,
+  b int not null
+);
+insert into t2 select seq,seq from seq_1_to_3;
+
+--echo # Must be converted to inner join:
+explain extended
+select * from t1, t2
+where
+  t1.a=1 and
+  t1.b=t2.b(+) and
+  t2.b=1;
+
+drop table t1,t2;
+
+
+--echo #
+--echo # MDEV-36838: Oracle outer join syntax (+): server crash on derived tables
+--echo #
+
+select a.a
+from (select 1 as a) a,
+     (select 2 as b) b
+     where a.a=b.b(+);
+
+--echo # End of 12.0 tests
diff --git a/sql/item.cc b/sql/item.cc
index 50b0ac6534a..9e13669992d 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -10258,9 +10258,9 @@ err:
 
 bool Item_field::ora_join_processor(void *arg)
 {
-  DBUG_ASSERT(cached_table);
+  DBUG_ASSERT(field->table->pos_in_table_list);
   return Item_ident::ora_join_add_table_ref((ora_join_processor_param *)arg,
-                                            cached_table);
+                                            field->table->pos_in_table_list);
 }