mysql中sql语句执行时间

delimiter // set @d=now();
select * from comment;
select timestampdiff(second,@d,now());
delimiter ;

Query OK, 0 rows affected (1 min 55.58 sec)

+----------------------------------+
| timestampdiff(second, @d, now()) |
+----------------------------------+
|                                2 |
+----------------------------------+
1 row in set (1 min 55.58 sec)