create table t1 (a int);

insert into t1 values (1),(2),(1);

explain extended select a, count(*) c from t1 group by a having c < 2;

show warnings;

drop table t1;

MariaDB [test]> explain extended select a, count(*) c from t1 group by a having c < 2;

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

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | filtered | Extra                           |

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

|    1 | SIMPLE      | t1    | ALL  | NULL          | NULL | NULL    | NULL |    3 |   100.00 | Using temporary; Using filesort |

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

1 row in set, 1 warning (0.091 sec)

MariaDB [test]> show warnings;

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

| Level | Code | Message                                                                                          |

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

| Note  | 1003 | select `test`.`t1`.`a` AS `a`,count(0) AS `c` from `test`.`t1` group by `test`.`t1`.`a` having 1 |

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

1 row in set (0.000 sec)

MariaDB [test]> explain extended select a, count(*) c from t1 group by a having c < 2;

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

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | filtered | Extra                           |

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

|    1 | SIMPLE      | t1    | ALL  | NULL          | NULL | NULL    | NULL |    3 |   100.00 | Using temporary; Using filesort |

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

1 row in set, 1 warning (0.000 sec)

MariaDB [test]> show warnings;

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

| Level | Code | Message                                                                                                  |

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

| Note  | 1003 | select `test`.`t1`.`a` AS `a`,count(0) AS `c` from `test`.`t1` group by `test`.`t1`.`a` having (`c` < 2) |

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

1 row in set (0.000 sec)

commit b532be9f8ce4872be4a3f1ef2fa296a1de347859 (HEAD)

Merge: a4c81986aad 0f62eee2f87

Author: Sergei Petrunia

Date:   Tue Apr 12 00:00:53 2016 +0200

    Merge ../10.2-window-funcs-r12 into 10.2