Question

I’m having some difficulty with my JOIN and IS NULL..

Basically what I want to do is find all members who are not apart of certain group category ID’s that I specify.

SELECT m.* FROM elvanto_members AS m
    LEFT JOIN elvanto_groups AS g ON g.deleted = 0
    LEFT JOIN elvanto_groups_categories AS gc ON gc.group_id = g.id AND (gc.category_id = '1' OR gc.category_id = '2')
    WHERE gr.id IS NULL

Some members aren’t apart of any group categories at all which is why I’ve made it a LEFT JOIN.

Am I making sense? Do you have any idea how to fix this?

Answer 1

Try this:

SELECT m.* FROM elvanto_members AS m
WHERE 
  not exists 
  (
    SELECT 1 FROM 
     elvanto_groups AS g 
      INNER JOIN elvanto_groups_categories AS gc ON 
        gc.group_id = g.id
    WHERE
     gc.category_id IN ('1','2') AND
     g.id = m.group_id AND
     g.deleted = 0
  )