我们如何将 AUTO_INCREMENT 应用于列?
mysqlmysqli database
AUTO_INCREMENT 表示该列将自动获取值。为了说明这一点，我们创建了一个表"employees"，如下所示 −
mysql> Show Create Table employees\G *************************** 1. row *************************** Table: employees Create Table: CREATE TABLE `employees` ( `Id` int(11) NOT NULL AUTO_INCREMENT, `Name` varchar(35) DEFAULT NULL, PRIMARY KEY (`Id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 1 row in set (0.00 sec)
从上面的结果集中，我们可以看到列 id 被赋予了自动增加选项。现在，当我们在 Name 字段中插入值时，id 字段将自动获取值 −
mysql> Insert Into employees(Name) Values('Ram');
Query OK, 1 row affected (0.09 sec)
mysql> Insert Into employees(Name) Values('Shyam');
Query OK, 1 row affected (0.03 sec)
mysql> Insert Into employees(Name) Values('Mohan');
Query OK, 1 row affected (0.04 sec)
mysql> Insert Into employees(Name) Values('Sohan');
Query OK, 1 row affected (0.04 sec)
mysql> Select * from employees;
+----+-------+
| Id | Name |
+----+-------+
| 1 | Ram |
| 2 | Shyam |
| 3 | Mohan |
| 4 | Sohan |
+----+-------+
4 rows in set (0.00 sec)
