I had an issue when I was trying to join two tables with one-to-many relationships.
If there is a table called STUDENTS
SubjectID StudentName
---------- -------------
1 Mary
1 John
1 Sam
2 Alaina
2 Edward
Result I expected was:
SubjectID StudentName
---------- -------------
1 Mary, John, Sam
2 Alaina, Edward
* Solution:
In MySQL there is a function, GROUP_CONCAT(), which allows you to concatenate the values from multiple rows. Example:
SELECT 1 AS a, GROUP_CONCAT(name ORDER BY name ASC SEPARATOR ', ') AS people
FROM users
WHERE id IN (1,2,3)
GROUP BY a
Revisions
- June 30, 2016 @ 15:47:10 [Current Revision] by admin
- June 30, 2016 @ 15:47:10 by admin
- June 30, 2016 @ 15:46:13 by admin
Revision Differences
There are no differences between the June 30, 2016 @ 15:47:10 revision and the current revision. (Maybe only post meta information was changed.)
No comments yet.