如何在MySQL中使用自增列?
要使用自增列,可以在创建表时将其设置为AUTO_INCREMENT。
让我们先创建一个表。在这里,我们将Id字段设置为列,因为这将是我们的自增列 –
mysql> create table DemoTable
-> (
-> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
-> FirstName varchar(20),
-> LastName varchar(20)
-> );
Query OK, 0 rows affected (0.71 sec)
使用insert命令在表中插入一些记录 –
mysql> insert into DemoTable(FirstName,LastName) values('John','Smith');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable(FirstName,LastName) values('Chris','Brown');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable(FirstName,LastName) values('Carol','Taylor');
Query OK, 1 row affected (0.21 sec)
使用select语句从表中显示所有记录 –
mysql> select *from DemoTable;
阅读更多:MySQL 教程
输出
+----+-----------+----------+
| Id | FirstName | LastName |
+----+-----------+----------+
| 1 | John | Smith |
| 2 | Chris | Brown |
| 3 | Carol | Taylor |
+----+-----------+----------+
3 rows in set (0.00 sec)