Question

I want to be able to find rows in Category table with condition of visible = 0 not in the query result from below:

SELECT c.id as cat_id, j.id
FROM category c
LEFT JOIN portfolio_job_category pjc
ON pjc.category_id = c.id
LEFT JOIN job j
ON j.id = pjc.job_id
WHERE c.visible = 0
AND j.end_date > CURRENT_DATE
GROUP BY c.id

Is there a way to use NOT IN to find this?

I tried below but this loops forever and crashes mysqld

SELECT c.id
FROM category c
WHERE c.id NOT IN
(SELECT c.id as cat_id, j.id
FROM category c
LEFT JOIN portfolio_job_category pjc
ON pjc.category_id = c.id
LEFT JOIN job j
ON j.id = pjc.job_id
WHERE c.visible = 0
AND j.end_date > CURRENT_DATE
GROUP BY c.id)
AND visible = 0

Answer 1

What don’t you try using LEFT JOIN

SELECT  a.ID
FROM    category a
        LEFT JOIN
        (
            SELECT  c.id as cat_id
            FROM    category c
                    LEFT JOIN portfolio_job_category pjc
                        ON pjc.category_id = c.id
                    LEFT JOIN job j
                        ON j.id = pjc.job_id
            WHERE   c.visible = 0 AND 
                    j.end_date > CURRENT_DATE
        ) b ON a.ID = b.ID
WHERE   b.ID IS NULL AND
        a.visible = 0