php - PHP MYSQL将统一值输出到同一表列

Question

我的 MySQL 中有一张表，如下所示

============================
id  | courses   | r_number  
----------------------------
1   | English   | C/009
2   | Maths     | C/009
3   | English   | C/003
4   | Maths     | C/002
============================

我如何将其输出为类似于下面的 HTML 表

====================================
id  | courses           | r_number  
------------------------------------
1   | English, Maths    | C/009
2   | English           | C/003
3   | Maths             | C/002
====================================

Answer 1

SELECT  MIN(ID) ID,
        GROUP_CONCAT(Courses SEPARATOR ', ') Courses,
        r_Number
FROM    TableName
GROUP   BY r_Number
ORDER   BY ID

• SQLFiddle 演示

我想知道为什么在您的示例ID中与记录不匹配，这是为什么呢？