一、报错
MySQL执行命令：
UPDATE user SET host = '%' WHERE user = 'root';
报错：
ERROR 1062 (23000): Duplicate entry '%-root' for key 'user.PRIMARY'
mysql> UPDATE user SET host = '%' WHERE user = 'root';
ERROR 1062 (23000): Duplicate entry '%-root' for key 'user.PRIMARY'二、原因
查看所有的用户
select host, user from user;
发现，有两个root用户，我们将host 为host的那条数据删除。
mysql> DELETE FROM user WHERE user = 'root' AND host = 'host';
Query OK, 1 row affected (0.01 sec)再次进行更新
mysql> update user set host='%' where user='root';
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0再次查看用户数据
mysql> select host, user from user;
+-----------+------------------+
| host | user |
+-----------+------------------+
| % | root |
| localhost | mysql.infoschema |
| localhost | mysql.session |
| localhost | mysql.sys |
+-----------+------------------+
4 rows in set (0.00 sec)此时HOST已经变成了%
最后使用更改生效
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.01 sec)
