Question

I need some solution to select photos which are marked as “public” or marked “for friends”. I don’t have an idea how is it possible.

Is it easy to select public photos:

        $result = mysql_query("SELECT filename, ownerid, etc... FROM photos 
WHERE public='1' order by id DESC limit $start, $step") or die('Error');

or even photos marked “for friends”

    $result = mysql_query("SELECT filename, ownerid, etc... FROM photos 
WHERE public='1' or for_friends='1' order by id DESC limit $start, $step") or die('Error');

But… each photo belongs to a different owner and before selecting them the query must know if I am a friend of the owner of this photo.

Answer 1

Assuming you have a friends table which maps users with their friends, having columns user_id and friend_user_id, then your query should be something like this :

SELECT * 
FROM photos p 
WHERE p.owner_id IN (SELECT friend_user_id 
                     FROM friends 
                     WHERE user_id = 1234 ) 
  AND (p.is_public = '1' OR p.for_friends = '1');