How to verify two distinct values belong to a field in MySQL - mysql

Question

I have the following MySQL query. As you can see in the last line, it asks for the filter_id to be either 51 or 8.
How can I modify this query to make sure the products that are returned are only products that have BOTH filter IDs.
What I did: I tried adding HAVING COUNT(DISTINCT pf.filter_id) >=2 based on other answers in this forum but it did not help.
SELECT COUNT(DISTINCT p.product_id) AS total
FROM ocb3l_product_to_category p2c
LEFT JOIN ocb3l_product_filter pf ON (p2c.product_id = pf.product_id)
LEFT JOIN ocb3l_product p ON (pf.product_id = p.product_id)
LEFT JOIN ocb3l_product_description pd ON (p.product_id = pd.product_id)
LEFT JOIN ocb3l_product_to_store p2s ON (p.product_id = p2s.product_id)
WHERE pd.language_id = '1'
AND p.status = '1'
AND p.date_available <= NOW()
AND p2s.store_id = '0'
AND p2c.category_id = '146'
AND pf.filter_id IN (51,8)
P.S. This query is used in an OpenCart shop to get the total number of products on the category pages.

Answer 1

The HAVING COUNT(DISTINCT pf.filter_id) >=2 clause will work, if you were to GROUP BY the product_id.
One approach is to use an inline view (derived table) so that this check can be performed for each product_id. The result from that can be joined to the other tables.
For example:
SELECT COUNT(DISTINCT fp.product_id) AS total
FROM (
SELECT p.product_id
FROM ocb3l_product p
JOIN ocb3l_product_filter pf
ON pf.product_id = p.product_id
AND pf.filter_id IN (51,8)
WHERE p.status = '1'
AND p.date_available <= NOW()
GROUP BY p.product_id
HAVING COUNT(DISTINCT pf.filter_id) = 2
) fp
JOIN ocb3l_product_to_category p2c
ON p2c.product_id = fp.product_id
AND p2c.category_id = '146'
JOIN ocb3l_product_to_store p2s
ON p2s.product_id = fp.product_id
AND p2s.store_id = '0'
JOIN ocb3l_product_description pd
ON pd.product_id = fp.product_id
AND pd.language_id = '1'

Answer 2

What you need to do is add another JOINed copy of the product_filter table like this:
SELECT COUNT(DISTINCT p.product_id) AS total
FROM ocb3l_product_to_category p2c
LEFT JOIN ocb3l_product_filter pf ON (p2c.product_id = pf.product_id)
LEFT JOIN ocb3l_product_filter pf2 ON (p2c.product_id = pf2.product_id) /*new*/
LEFT JOIN ocb3l_product p ON (pf.product_id = p.product_id)
LEFT JOIN ocb3l_product_description pd ON (p.product_id = pd.product_id)
LEFT JOIN ocb3l_product_to_store p2s ON (p.product_id = p2s.product_id)
WHERE pd.language_id = '1'
AND p.status = '1'
AND p.date_available <= NOW()
AND p2s.store_id = '0'
AND p2c.category_id = '146'
AND pf.filter_id = 51 /*used to be IN (51,8)*/
AND pf2.filter_id = 8 /*new*/