April 6, 2012
MySQL query for mutual friends
Question by george
Possible Duplicate:
MYSQL select mutual friends
I have a table for friendship, the friendship is stored only in one line. So there is no duplicate entries.
id Person1 Person2 status
1 1 2 friend
2 1 3 friend
3 2 3 friend
4 3 4 friend
What MySQL query (join, inner join) will help me to find common (mutual) friends between person #1 and person #3? The input in this example is {1,3} and the output should be {2} since Person #2 is friend with bot #1 and #3.
Answer by Starx
I think this is rather simply achieved by this
SELECT * FROM friends
WHERE
(Person1 = '1' or Person2 = '1') &&
(Person1 = '2' or Person2 = '2') &&
status = 'friend'
Given that the you are trying to find mutual between person 1 and 2
