我有三张桌子，大学课程，大学课程，其中大学课程是大学课程与课程之间多对多关系的中间表。
college_details
+------------+--------------+
| college_id | college_name |
+------------+--------------+
| 1 | abc, Nagpur |
| 2 | xyz, Nagpur |
| 3 | mnop, Nagpur |
+------------+--------------+
college_courses
+------------+--------------+
| college_id | course_id |
+------------+--------------+
| 1 | 1 |
| 1 | 5 |
| 2 | 3 |
| 3 | 5 |
+---------------------------+
当然
+----------+-------------+
|course_id | course_name |
+----------+-------------+
| 1 | B.E |
| 2 | M.E |
| 3 | M.Tech |
| 4 | B.Tech |
| 5 | M.B.A |
+----------+-------------+
SELECT cd.college_id
, cd.college_name
, c.course_name
FROM college_details AS cd
LEFT
JOIN college_courses AS cc
ON cc.college_id = cd.college_id
LEFT
JOIN course AS c
ON cc.course_id = c.course_id
从上面的查询我得到下表。
+------------+---------------+-------------+
| college_id | college_name | course_name |
+------------+---------------+-------------+
| 1 | abc, college | be |
| 1 | abc, college | mba |
| 2 | xyz, college | me |
| 3 | mnop, college | btech |
+------------+---------------+-------------+
查询 - ＆gt; "SELECT cd.college_id,cd.college_name,GROUP_CONCAT(c.course_name) FROM college_details AS cd LEFT JOIN college_courses AS cc ON cc.college_id = cd.college_id LEFT JOIN course AS c ON cc.college_id = c.course_id ";
从上面的查询我得到下表。
+------------+--------------+-----------------------------+
| college_id | college_name | GROUP_CONCAT(c.course_name) |
+------------+--------------+-----------------------------+
| 1 | abc, college | be,be,me,btech |
+------------+--------------+-----------------------------+
但我想要的是下表。
+------------+---------------+-------------+
| college_id | college_name | course_name |
+------------+---------------+-------------+
| 1 | abc, college | be,mba |
| 2 | xyz, college | me |
| 3 | mnop, college | btech |
+------------+---------------+-------------+