從 MySQL 表格中刪除資料後,如何自動增量 1?
為此,可以使用 TRUNCATE TABLE 命令。我們先建立一個表 −
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 命令向表中插入一些記錄−
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 語句顯示錶中的所有記錄
mysql> select * from DemoTable1796;
這將生成以下輸出
+-----------+--------------+ | StudentId | StudentName | +-----------+--------------+ | 1 | Chris Brown | | 2 | David Miller | | 3 | John Doe | +-----------+--------------+ 3 rows in set (0.00 sec)
這是從表中刪除記錄的查詢−
mysql> delete from DemoTable1796; Query OK, 3 rows affected (0.00 sec)
現在向表中插入一條記錄
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)現在可以使用 TRUNCATE TABLE 命令
mysql> truncate table DemoTable1796; Query OK, 0 rows affected (0.00 sec)
現在,讓我們向表中插入一些記錄
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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