MySQL 如何在从表中删除数据后自动增加1

为此，您可以使用TRUNCATE TABLE命令。首先，让我们创建一张表-

mysql> create table DemoTable1796
     (
     StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
     StudentName varchar(20)
     );
Query OK, 0 rows affected (0.00 sec)

使用insert命令在表中插入一些记录-

mysql> insert into DemoTable1796(StudentName) values('Chris Brown');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1796(StudentName) values('David Miller');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1796(StudentName) values('John Doe');
Query OK, 1 row affected (0.00 sec)

使用select语句显示表中的所有记录-

mysql> select * from DemoTable1796;

这将产生以下输出-

+-----------+--------------+
| StudentId | StudentName  |
+-----------+--------------+
|         1 | Chris Brown  |
|         2 | David Miller |
|         3 | John Doe     |
+-----------+--------------+
3 rows in set (0.00 sec)

这里是从表中删除记录的查询-

mysql> delete from DemoTable1796;
Query OK, 3 rows affected (0.00 sec)

现在将一条记录插入表中-

mysql> insert into DemoTable1796(StudentName) values('John Doe');
Query OK, 1 row affected (0.00 sec)
mysql> select * from DemoTable1796;
+-----------+-------------+
| StudentId | StudentName |
+-----------+-------------+
|         4 | John Doe    |
+-----------+-------------+
1 row in set (0.00 sec)

现在您可以使用TRUNCATE TABLE命令-

mysql> truncate table DemoTable1796;
Query OK, 0 rows affected (0.00 sec)

现在，让我们向表中插入一些记录-

mysql> insert into DemoTable1796(StudentName) values('John Doe');
Query OK, 1 row affected (0.00 sec)
mysql> select * from DemoTable1796;
+-----------+-------------+
| StudentId | StudentName |
+-----------+-------------+
|         1 | John Doe    |
+-----------+-------------+
1 row in set (0.00 sec)

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