having '2015-01-01 01:00:00.000001' > coalesce(NULL) returns true

mysql> drop table if exists t1;

Query OK, 0 rows affected (0.00 sec)

mysql> create table t1(c1 datetime(0));

nsert inQuery OK, 0 rows affected (0.01 sec)

mysql> insert into t1 values(null);

Query OK, 1 row affected (0.00 sec)

mysql> select * from t1 having '2015-01-01 01:00:00.000001' > coalesce(c1);

+------+

| c1   |

+------+

| NULL |

+------+

1 row in set (0.00 sec)

mysql> select version();

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

| version()       |

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

| 10.1.10-MariaDB |

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

1 row in set (0.00 sec)

drop table if exists t1;

create table t1(c1 datetime(0));

insert into t1 values(null);

select * from t1 having '2015-01-01 01:00:00.000001' > coalesce(c1);