使用PHP从MySQL获取好友列表

Question

I have to tables in MySQL database, USERS and FRIENDS. They have this structure:

USERS TABLE:

FRIENDS TABLE (two users are friends ONLY if exists two rows like in the image):

I want to create a MySQL query in PHP to SELECT the nombre (name) of the users that are my friends. I read that I have to use the operator LEFT JOIN but I did not succeed.

Thank you!

Answer 1

Try using INNER JOIN instead. Try below query -

SELECT users.nombre FROM users INNER JOIN friends ON 
(users.id = friends.usuari_o OR users.id = friends.usuari_t)
WHERE (friends.usuari_o = $id OR friends.usuari_t = $id);