MariaDB [test]> create table c1 (a int)engine=columnstore;

Query OK, 0 rows affected (0.381 sec)

MariaDB [test]> insert into c1 values (1), (2), (3);

Query OK, 3 rows affected (0.233 sec)

Records: 3  Duplicates: 0  Warnings: 0

MariaDB [test]> create table c2 (a int)engine=columnstore;

Query OK, 0 rows affected (0.338 sec)

MariaDB [test]> insert into c2 values (2);

Query OK, 1 row affected (0.109 sec)

MariaDB [test]> create table c3 (a int)engine=columnstore;

Query OK, 0 rows affected (0.327 sec)

MariaDB [test]> create table c4 (a int)engine=columnstore;

Query OK, 0 rows affected (0.336 sec)

MariaDB [test]> create table c5 (a int)engine=columnstore;

Query OK, 0 rows affected (0.361 sec)

MariaDB [test]> select * from

    -> (

    ->  select c1.a as col1, c2.a as col2 from

    ->   c1 left join

    ->   (

    ->    (c2 left join c3 on c2.a=c3.a) left join

    ->    (c4 left join c5 on c4.a=c5.a)

    ->    on c2.a=c4.a

    ->   )

    ->   on c1.a=c2.a

    -> ) h;

ERROR 1815 (HY000): Internal error: IDB-1000: 'c1' and 'c2, c3, c4, c5' are not joined.

MariaDB [test]> select c1.a as col1, c2.a as col2 from

    ->   c1 left join

    ->   (

    ->    (c2 left join c3 on c2.a=c3.a) left join

    ->    (c4 left join c5 on c4.a=c5.a)

    ->    on c2.a=c4.a

    ->   )

    ->   on c1.a=c2.a;

+------+------+

| col1 | col2 |

+------+------+

|    1 | NULL |

|    2 |    2 |

|    3 | NULL |

+------+------+

3 rows in set (0.021 sec)