+--------+----------+----------+-------+-------+
| 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
| 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
-> 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 / ACMAIN
mysql> 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>
改成整数:
Alter table `你的表名` modify `password` int(11) NOT NULL; 改成字符串:
Alter table `你的表名` modify `password` varchar(20) NOT NULL; 写法一样的