增加记录：
注：null关键字与auto_increment限制条件相结合，可以为字段自动赋值；字段必须全，且一一对应；字符型用单引号；
1 mysql> insert into test values('sunshine_habit','hello_world_lyq@163.com'
2 -> ,1558888888,null);
输出：
3 Query OK, 1 row affected (0.10 sec)
查询记录：
1 mysql> select * from test where name='sunshine_habit';
2 输出：
3 +----------------+-------------------------+--------------+----+
4 | name | email | phone_number | id |
5 +----------------+-------------------------+--------------+----+
6 | sunshine_habit | hello_world_lyq@163.com | 1558888888 | 1 |
7 +----------------+-------------------------+--------------+----+
8 1 row in set (0.00 sec)
修改记录：
1 mysql> update test set name='Sam' where name='sunshine';
输出：
2 Query OK, 1 row affected (0.06 sec)
3 Rows matched: 1 Changed: 1 Warnings: 0
删除记录
1 mysql> delete from test where name='Snow White';
2 Query OK, 1 row affected (0.08 sec)
