How to get a user's friends' names? I have a users table and friends table. The user with ID 1 has 4 friends (with IDs 2,3,4,13). I want to get names and surnames of users 2,3,4 and 13. I can to it with standard queries but it will slow down the process; querying for every friend. I didn't get how and what to use of left, joints, right joints, simple joints, ASs, ONs, ...
If you want to get the names of the friends for a user perhaps try something like so:

SELECT u.firstname, u.surname 
FROM friend f, user u
WHERE (f.Person1 = 1 OR f.Person2 = 1)


This should get a back a list of names in your user table (providing that is what you have named your friends in the user table) that are friends with userID 1

I'm guessing your friend table contains the foreign key IDs of the friends making up the partnership?