Home Database Mysql Tutorial MySql采用GROUP_CONCAT合并多条数据显示的方法

MySql采用GROUP_CONCAT合并多条数据显示的方法

Jun 07, 2016 pm 04:27 PM
concat mysql merge data use

本文实例讲述了MySql采用GROUP_CONCAT合并多条数据显示的方法,分享给大家供大家参考。具体实现方法如下: 假设有这样一个需求: 1:班级表: id class_name 2:学生表: id name class_id 如果我们要查所有的班级以及每个班级下的学生,你一定会想到这样写法:

本文实例讲述了MySql采用GROUP_CONCAT合并多条数据显示的方法,分享给大家供大家参考。具体实现方法如下:

假设有这样一个需求:
1:班级表:
id class_name
2:学生表:
id name class_id
 
如果我们要查所有的班级以及每个班级下的学生,你一定会想到这样写法:

SELECT
banji.*, user.name
FROM `banji`
left join user
on banji.id=user.`class`
where banji.id=2


这样我们得到的结果的个数是和学生人数相同的,而我希望得到的就是一条数据,而这条数据中还要包含所有学生,可以这样写:

SELECT
banji.*, GROUP_CONCAT(user.name) as names
FROM `banji`
left join user
on banji.id=user.`class`
where banji.id=2


这样就只得到一条结果了,而结果中包含所有的学生name,
id class_name  names
2  lisi,zhaoliu,liu,小二,xiaoming,小张

还可以自定义分隔符:

SELECT
banji.*, GROUP_CONCAT(user.name SEPARATOR "|") as names
FROM `banji`
left join user
on banji.id=user.`class`
where banji.id=2


得到的结果:

id class_name  names
2  lisi|zhaoliu|liu|小二|xiaoming|小张

 二  希望本文所述对大家的MySQL数据库程序设计有所帮助。
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