MySQL COUNT(subquery)

Question

My MySQL query:

 SELECT id, name, depth, restricted, order, parent_id,
    (SELECT COUNT(t2.id) AS count FROM #__webshop_product_color_dbar AS t2
        WHERE t2.product_id =
            (SELECT product_id FROM #__webshop_category_product AS t3
            WHERE t3.category_id = "0")
        AND available < 0 OR stock = "Y" OR infinite_amount = "Y"
    ) AS productcount
    FROM #__webshop_category AS t1
    WHERE parent_id = "'.$parent_id.'" AND depth = "'.$depth.'" AND restricted="N"
    ORDER BY id ASC

My problem is: all product count = 2; if i use "WHERE t2.product_id IN", it does not work.

What is the problem?

(Sorry for my bad english)

Answer 1

The subselects are not linked to t1.id, The following joins restores that link.
I'm not 100% sure it's what you want without more info on the relationships between the tables, but it should be close.

SELECT t1.id, t1.name, t1,depth, t1.restricted, t1.order, t1.parent_id
  , COUNT(t2.id) as productcount
FROM #__webshop_category AS t1
LEFT JOIN #__webshop_product_color_dbar AS t3 on (t3.category_id = t1.id)
LEFT JOIN #__webshop_product_color_dbar AS t2 ON 
  (
  t2.product_id = t3.product_id AND t2.available < 0 
    OR stock = 'Y' OR infinite_amount = 'Y'
  )
WHERE t1.parent_id = "'.$parent_id.'" 
  AND t1.depth = "'.$depth.'" 
  AND t1.restricted = 'N'
GROUP BY t1.id

Note that the GROUP BY already orders the items ASC, so no extra ORDER BY is needed.