mysql - 记录转换1列3行->1行3列

Question

首先看下面的查询

SELECT COUNT(id) AS total_record, id, modeller,
  MONTHNAME(completed_date) AS current_month,
  QUARTER(completed_date) AS current_quarter,
  Difficulty,
  YEAR(completed_date) AS current_year
FROM model
WHERE modeller != ''
  AND completed_date BETWEEN '2010-04-01'
  AND '2010-05-31' AND Difficulty != ''
GROUP BY Difficulty,
MONTH(completed_date) ORDER BY
MONTH(completed_date) ASC

我得到的结果是

Modeller  Month  Year  Difficulty

XYZ       Jan    2010  23

XYZ       Jan    2010  14

XYZ       Jan    2010  15

ABC       Feb    2010   5

ABC       Feb    2010  14

ABC       Feb    2010   6

我想要这样的结果

Modeller  Month  Year  Difficulty

XYZ       Jan    2010  23, 14, 15

ABC       Feb    2010  5, 14, 6

我的数据库是 MySQL，用于我正在开发的应用程序，因此我们将非常感谢任何帮助。

Answer 1

看看GROUP_CONCAT