MySQL GROUP BY multiple columns and fields

Question

I've tried to search answer here, there are few questions are quite similar with my question but i still can't figure out how to GROUP BY below.

MYSQL Structure:

ID | USERID | FRIENDID 
1  |   14   |    65
2  |   65   |    14
3  |   12   |    19
4  |   19   |    12

How to GROUP BY ID 1 & ID 2 and ID 3 & ID 4 with php query?

Result:

1. 14 & 65 
2. 12 & 19

Answer 1

SELECT LEAST(USERID, FRIENDID) as x, 
       GREATEST(USERID, FRIENDID) as y
FROM   TableName
GROUP  BY x, y

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