how to get SUM from two different tables that are linked to third one

Question

ok the problem is that I have to sum two sums from two tables that are linked

first table points:

id | user_id | point | hit
1  | 1       |     4 | yes
2         


        

Answer 1

If you want total earnings per user, you should probably start by identifying which users you want earnings for. The most sensible option is probably to use the users table itself as the basis.

SELECT user_id,
       (SELECT SUM(point)
          FROM points
         WHERE user_id = u.user_id
       )
       +
       (SELECT SUM(earning)
          FROM earnings
         WHERE user_id = u.user_id
           AND p.hit IN ('yes', 'no')
       ) AS bb
  FROM users

This approach has the added benefit of reporting on users who had no points and/or earnings.