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