MySQL的COUNT（子查詢）

Question

我的MySQL查詢：

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 

我的問題是：所有的產品數= 2; 如果我使用「WHERE t2.product_id IN」，它不起作用。

什麼問題？

（對不起我的英文不好）

Answer 1

的子查詢未鏈接到t1.id，下面的連接恢復該鏈接。
我不是100％確定這是你想要的，但沒有關於表格之間關係的更多信息，但它應該接近。

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 

注意，GROUP BY已定購物品ASC，因此不需要額外的ORDER BY。