语法规则 SELECT column_name(s)FROM table_name1INNER JOIN table_name2 ON table_name1.column_name=table_name2.column_name 先创建两个表，1.用户，2.用户类别 用户表 CREATE TABLE `user` ( `id` int(32) NOT NULL AUTO_INCREMENT,
语法规则
SELECT column_name(s)
FROM table_name1
INNER JOIN table_name2
ON table_name1.column_name=table_name2.column_name
先创建两个表，1.用户，2.用户类别
用户表
CREATE TABLE `user` (
`id` int(32) NOT NULL AUTO_INCREMENT,
`name` varchar(16) NOT NULL,
`kindid` int(32) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
用户类别表
CREATE TABLE `userkind` (
`id` int(32) NOT NULL AUTO_INCREMENT,
`kindname` varchar(16) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
插入一些数据到user表
INSERT INTO `user` VALUES (1,'小明',1),(2,'小红',1),(3,'涵涵',2);插入一些数据到 userkind表
INSERT INTO `userkind` VALUES (1,'普通会员'),(2,'VIP会员');
如图：
下面是控制台的查询例子：
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mysql> use join;
Database changed
mysql> select * from `user`;
+----+------+--------+
| id | name | kindid |
+----+------+--------+
| 1 | 小明 | 1 |
| 2 | 小红 | 1 |
| 3 | 涵涵 | 2 |
+----+------+--------+
3 rows in set (0.00 sec)
mysql> select * from `userkind`;
+----+----------+
| id | kindname |
+----+----------+
| 1 | 普通会员 |
| 2 | VIP会员 |
+----+----------+
2 rows in set (0.00 sec)
mysql> select * from `user` inner join `userkind` on user.kindid=userkind.id;
+----+------+--------+----+----------+
| id | name | kindid | id | kindname |
+----+------+--------+----+----------+
| 1 | 小明 | 1 | 1 | 普通会员 |
| 2 | 小红 | 1 | 1 | 普通会员 |
| 3 | 涵涵 | 2 | 2 | VIP会员 |
+----+------+--------+----+----------+
3 rows in set (0.02 sec)
mysql> select `id` as `用户ID`,`name` as `用户名`,`kindname` as `用户类别` from
`user` inner join `userkind` where user.kindid=userkind.id;
ERROR 1052 (23000): Column 'id' in field list is ambiguous
mysql> select `user`.`id` as `用户ID`,`name` as `用户名`,`kindname` as `用户类别
` from
-> `user` inner join `userkind` where `user`.`kindid`=`userkind`.`id`;
+--------+--------+----------+
| 用户ID | 用户名 | 用户类别 |
+--------+--------+----------+
| 1 | 小明 | 普通会员 |
| 2 | 小红 | 普通会员 |
| 3 | 涵涵 | VIP会员 |
+--------+--------+----------+
3 rows in set (0.00 sec)
mysql> select `user`.`id` as `用户ID`,`name` as `用户名`,`kindname` as `用户类别
` from `user` inner join `userkind` on `user`.`kindid`=`userkind`.`id`;
+--------+--------+----------+
| 用户ID | 用户名 | 用户类别 |
+--------+--------+----------+
| 1 | 小明 | 普通会员 |
| 2 | 小红 | 普通会员 |
| 3 | 涵涵 | VIP会员 |
+--------+--------+----------+
3 rows in set (0.00 sec)
mysql>
需要注意的是： 这里的on 基本等价于where(本人感觉)
当 column （字段） 两个表都有 却分不清时，需要用`表名`.`字段名` 进行分辨。
as就是取别名了。看上面例子就知道！
以上这篇Mysql inner join on的用法实例(必看)就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持每日运维。
