Question

I’m trying to join 3 tables that hold values for users – their id and username, and table engine4_storage_files that has info about users profile picture. If user hasn’t uploaded it’s profile pic, there isn’t a record in sf table – but I want to query all users regardless of weather the pic is uploaded or not.

SELECT p.user_id as gledalac, sf.storage_path, 
       u.displayname, u.username
FROM engine4_pregledi p JOIN 
     engine4_storage_files sf JOIN 
     engine4_users u
WHERE p.subject_id = 1
AND   p.user_id = u.user_id
AND   sf.parent_id = u.user_id
AND   sf.parent_type =  'user'
AND   sf.type =  'thumb.icon'
AND   sf.parent_file_id = u.photo_id
order by datum desc limit 10

This query returns 3 users with path to their images, but actually there are 4 users to be shown, but 4th user doesn’t have profile image – so he’s not included in query result.

Is there a way to include 4th user that doesn’t have profile image into query results?

Answer 1

use LEFT JOIN instead,

SELECT  p.user_id as gledalac, 
        sf.storage_path, 
        u.displayname, 
        u.username
FROM    engine4_pregledi p 
        LEFT JOIN engine4_users u 
            ON p.user_id = u.user_id
        LEFT JOIN engine4_storage_files sf 
            ON  sf.parent_id = u.user_id AND 
                sf.parent_type =  'user' AND 
                sf.type =  'thumb.icon' AND 
                sf.parent_file_id = u.photo_id
WHERE   p.subject_id = 1 
ORDER   BY datum DESC 
LIMIT   10

To fully gain knowledge about joins, kindly visit the link below:

• Visual Representation of SQL Joins