MySQL 如何已经创建的表中插入auto_increment

使用ALTER命令。让我们首先创建一个表 –

mysql> create table DemoTable
-> (
-> StudentName varchar(100)
-> );
Query OK, 0 rows affected (0.46 sec)

这是插入auto_increment的查询 –

mysql> alter table DemoTable ADD COLUMN StudentId int NOT NULL;
Query OK, 0 rows affected (0.50 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> alter table DemoTable ADD PRIMARY KEY(StudentId);
Query OK, 0 rows affected (1.23 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> alter table DemoTable CHANGE StudentId StudentId int NOT NULL 
AUTO_INCREMENT;
Query OK, 0 rows affected (2.20 sec)
Records: 0 Duplicates: 0 Warnings: 0

使用insert命令在表中插入记录 –

mysql> insert into DemoTable(StudentName) values('Chris');
Query OK, 1 row affected (0.17 sec)

mysql> insert into DemoTable(StudentName) values('David');
Query OK, 1 row affected (0.15 sec)

使用select语句显示表中的所有记录

mysql> select *from DemoTable;

阅读更多：MySQL 教程

输出

这将生成以下输出 –

+-------------+-----------+
| StudentName | StudentId |
+-------------+-----------+
| Chris       | 1         |
| David       | 2         |
+-------------+-----------+
2 rows in set (0.00 sec)