1、前置条件
MySQL数据库中存在表user_info，其结构和数据如下：
mysql> desc user_info;
+-----------+----------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+----------+------+-----+---------+-------+
| id | int(10) | NO | PRI | NULL | |
| name | char(20) | NO | | NULL | |
| passwd | char(40) | NO | | NULL | |
| email | char(20) | NO | | NULL | |
| phone | char(20) | NO | | NULL | |
| role | char(10) | NO | | NULL | |
| sex | char(10) | NO | | NULL | |
| status | int(10) | NO | | NULL | |
| createAt | datetime | NO | | NULL | |
| exprAt | datetime | NO | | NULL | |
| validDays | int(10) | NO | | NULL | |
| delAt | datetime | YES | | NULL | |
+-----------+----------+------+-----+---------+-------+
12 rows in set (0.10 sec)
mysql> select * from user_info;
+----+--------------+----------+------------+-------------+--------+------+--------+---------------------+---------------------+-----------+-------+
| id | name | passwd | email | phone | role | sex | status | createAt | exprAt | validDays | delAt |
+----+--------------+----------+------------+-------------+--------+------+--------+---------------------+---------------------+-----------+-------+
| 1 | StephenWang7 | py123456 | [email protected] | 15103887470 | admin | male | 200 | 2019-04-12 20:11:30 | 2019-04-19 20:11:30 | 30 | NULL |
| 2 | StephenWang8 | 123456 | [email protected] | 15103887470 | viewer | male | 200 | 2019-04-12 20:11:30 | 2019-04-19 20:11:30 | 30 | NULL |
+----+--------------+----------+------------+-------------+--------+------+--------+---------------------+---------------------+-----------+-------+
2 rows in set (0.00 sec)mysq
