MariaDB [test]> show create table i1;

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

| Table | Create Table                                                                              |

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

| i1    | CREATE TABLE `i1` (

  `a` varchar(30) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

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

1 row in set (0.001 sec)

MariaDB [test]> show create table i2;

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

| Table | Create Table                                                                              |

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

| i2    | CREATE TABLE `i2` (

  `a` varchar(30) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1 |

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

1 row in set (0.001 sec)

MariaDB [test]> select * from i1;

+------+

| a    |

+------+

| abc  |

| bcd  |

| cde  |

+------+

3 rows in set (0.001 sec)

MariaDB [test]> select * from i2;

+------+

| a    |

+------+

| bcd  |

| cde  |

| def  |

| efg  |

+------+

4 rows in set (0.001 sec)

MariaDB [test]> select a from i1 union all select a from i2 order by a;

+------+

| a    |

+------+

| abc  |

| bcd  |

| bcd  |

| cde  |

| cde  |

| def  |

| efg  |

+------+

7 rows in set (0.002 sec)

MariaDB [test]> show create table t1;

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

| Table | Create Table                                                                                   |

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

| t1    | CREATE TABLE `t1` (

  `a` varchar(30) DEFAULT NULL

) ENGINE=Columnstore DEFAULT CHARSET=latin1 |

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

1 row in set (0.001 sec)

MariaDB [test]> show create table t2;

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

| Table | Create Table                                                                                   |

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

| t2    | CREATE TABLE `t2` (

  `a` varchar(30) DEFAULT NULL

) ENGINE=Columnstore DEFAULT CHARSET=latin1 |

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

1 row in set (0.001 sec)

MariaDB [test]> select * from t1;

+------+

| a    |

+------+

| abc  |

| bcd  |

| cde  |

+------+

3 rows in set (0.019 sec)

MariaDB [test]> select * from t2;

+------+

| a    |

+------+

| bcd  |

| cde  |

| def  |

| efg  |

+------+

4 rows in set (0.011 sec)

MariaDB [test]> select a from t1 union all select a from t2 order by a;

+------+

| a    |

+------+

| abc  |

| bcd  |

| cde  |

| bcd  |

| cde  |

| def  |

| efg  |

+------+

7 rows in set (0.028 sec)