mysql设置非空有关问题

mysql设置非空问题
+--------+----------+----------+-------+-------+
| userid | password | username | email | phone |
+--------+----------+----------+-------+-------+
| 110 | 123456 | 111110 | NULL | NULL |

+--------+----------+----------+-------+-------+

在创建时没设置为空
  表创建完成后
  当表中没记录 我要设置 让password为非空 SQL语句怎么写


[解决办法]
Alter table `你的表名` modify `password` varchar(20) NOT NULL;
[解决办法]

SQL code

mysql> create table t_zhyou110z (    ->  userid int primary key,    ->  password varchar(10)    -> );Query OK, 0 rows affected (0.13 sec)mysql> desc t_zhyou110z;+----------+-------------+------+-----+---------+-------+| Field    | Type        | Null | Key | Default | Extra |+----------+-------------+------+-----+---------+-------+| userid   | int(11)     | NO   | PRI | NULL    |       || password | varchar(10) | YES  |     | NULL    |       |+----------+-------------+------+-----+---------+-------+2 rows in set (0.11 sec)-- 修改password 为not null / ACMAINmysql> alter table t_zhyou110z modify password varchar(10) not null;Query OK, 0 rows affected (0.22 sec)Records: 0  Duplicates: 0  Warnings: 0mysql> desc t_zhyou110z;+----------+-------------+------+-----+---------+-------+| Field    | Type        | Null | Key | Default | Extra |+----------+-------------+------+-----+---------+-------+| userid   | int(11)     | NO   | PRI | NULL    |       || password | varchar(10) | NO   |     | NULL    |       |+----------+-------------+------+-----+---------+-------+2 rows in set (0.00 sec)mysql>
[解决办法]
探讨

3Q 还是你们呢 这样写还可以长度 要修改类型怎么写呢