bitscn.com 1.计算数据表中一共有多少记录sql语句 mysql> select count(*) from openes; +----------+ | count(*) | +----------+ |      136 | +----------+ 1 row in set (0.00 sec)  2.查询字段类型为datetime的sql语句：   mysql> select * from biders where author_id =2253 and created_at between   '2012-3-19   00:00:00 '   and   '2012-3-19   23:59:59 '; +----+-----------+---------------------+---------------------+---------------------+ | id | author_id | created_at          | updated_at          | num_of_target_files | +----+-----------+---------------------+---------------------+---------------------+ |  10 |      2353 | 2012-3-19 15:21:08 | 2012-3-19 15:21:08 |                null | +----+-----------+---------------------+---------------------+---------------------+ 1 row in set (0.00 sec)    作者 hllnihao bitscn.com