MySQL-如何修复删除行从1,2,3,4,5到1,3,5的自动增量字段）。现在我们希望它是1,2,3
让我们首先创建一个表-
mysql> create table DemoTable1955 ( UserId int NOT NULL AUTO_INCREMENT , PRIMARY KEY(UserId) );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable1955 values(); mysql> insert into DemoTable1955 values(); mysql> insert into DemoTable1955 values(); mysql> insert into DemoTable1955 values(); mysql> insert into DemoTable1955 values();
使用select语句显示表中的所有记录-
mysql> select * from DemoTable1955;
这将产生以下输出-
+--------+ | UserId | +--------+ | 1 | | 2 | | 3 | | 4 | | 5 | +--------+ 5 rows in set (0.00 sec)
这是从表中删除行的查询-
mysql> delete from DemoTable1955 where UserId IN(2,4);
现在检查表记录-
mysql> select * from DemoTable1955;
这将产生以下输出-
+--------+ | UserId | +--------+ | 1 | | 3 | | 5 | +--------+ 3 rows in set (0.00 sec)
这是修复已删除行（1,2,3,4,5至1,3,5）的自动增量字段的查询。下面的查询将使列从1开始像1,2,3-
mysql> update DemoTable1955 set UserId = (@increment_value := @increment_value+ 1) order by UserId; Rows matched: 3 Changed: 2 Warnings: 0
让我们再次检查表记录-
mysql> select * from DemoTable1955;
这将产生以下输出-
+--------+ | UserId | +--------+ | 1 | | 2 | | 3 | +--------+ 3 rows in set (0.00 sec)