我似乎无法重新创建一个已删除的简单用户，即使是 MySQL 中的 root。

我的案例：用户“jack”之前存在，但我从 mysql.user
中删除了它以重新创建它。我在那张桌子上看不到任何痕迹。如果我为其他一些随机用户名执行此命令，例如“jimmy”，它可以正常工作（就像它最初为“jack”所做的那样）。

我对损坏用户“jack”做了什么？如何撤消该损坏以重新创建“jack”作为此 MySQL 安装的有效用户？

请参见下面的示例。（当然，最初，“杰克”的创作和他的撤职之间有很长的时间。）

mysql> CREATE USER 'jack'@'localhost' IDENTIFIED BY 'test123';
Query OK, 0 rows affected (0.00 sec)

mysql> select user,host from user;
+------------------+-----------------+
| user             | host            |
+------------------+-----------------+
| root             | 127.0.0.1       |
| debian-sys-maint | localhost       |
| jack             | localhost       |
| root             | localhost       |
| root             | russ-elite-book |
+------------------+-----------------+
5 rows in set (0.00 sec)

mysql> delete from user where user = 'jack';
Query OK, 1 row affected (0.00 sec)

mysql> select user,host from user;
+------------------+-----------------+
| user             | host            |
+------------------+-----------------+
| root             | 127.0.0.1       |
| debian-sys-maint | localhost       |
| root             | localhost       |
| root             | russ-elite-book |
+------------------+-----------------+
4 rows in set (0.00 sec)

mysql> CREATE USER 'jack'@'localhost' IDENTIFIED BY 'test123';
ERROR 1396 (HY000): Operation CREATE USER failed for 'jack'@'localhost'
mysql> CREATE USER 'jimmy'@'localhost' IDENTIFIED BY 'test123';
Query OK, 0 rows affected (0.00 sec)

mysql> select user,host from user;
+------------------+-----------------+
| user             | host            |
+------------------+-----------------+
| root             | 127.0.0.1       |
| debian-sys-maint | localhost       |
| jimmy            | localhost       |
| root             | localhost       |
| root             | russ-elite-book |
+------------------+-----------------+
5 rows in set (0.00 sec)