操作数应包含1列错误

Question

我有一个sql查询，由于链接产品的产品id重复，它返回了一些不正确的结果，所以我在查询的末尾添加了以下内容，希望它只接受任何产品id的第一个实例：

AND pc.products_id 
IN
(SELECT
pc.products_id, MIN(categories_id)
FROM
zen_products_to_categories pc
GROUP BY
pc.products_id)

但是当我运行进程时，我得到的操作数应该包含1列错误。我自己运行了这个查询，它只给我每个产品id一次，所以不确定为什么会出现错误。

我现在的完整查询是：

SELECT p.products_quantity, p.abebooks_status, 
p.products_id AS id, 
p.products_status AS prodStatus, 
FORMAT( IFNULL(s.specials_new_products_price, p.products_price),2) AS price, 
pc.categories_id AS prodCatID, 
c.parent_id AS catParentID, 
cd.categories_name AS catName 
FROM 
zen_products p 
JOIN zen_products_description pd ON p.products_id=pd.products_id 
JOIN zen_products_to_categories pc ON p.products_id=pc.products_id 
JOIN zen_categories c ON pc.categories_id=c.categories_id 
JOIN zen_categories_description cd ON c.categories_id=cd.categories_id 
left join zen_specials s on ( s.products_id = p.products_id AND ( (s.expires_date > CURRENT_DATE) OR (s.expires_date = 0) ) ) 
WHERE p.products_price > 0 and p.products_status = 1 
AND pc.products_id 
IN 
(SELECT pc.products_id, MIN(categories_id) 
FROM zen_products_to_categories pc GROUP BY pc.products_id) 
ORDER BY catName ASC 

有人能告诉我为什么当我添加额外的查询时它不起作用吗，因为它让我感到困惑

Answer 1

您可以尝试使用：

AND (pc.products_id, pc.categories_id) 
    IN
    (SELECT
       pc.products_id, MIN(categories_id)
     FROM
       zen_products_to_categories pc
     GROUP BY
       pc.products_id)

编辑：

在MySQL中，像这样的子查询通常很慢。你应该有更好的运气加入：

SELECT ....
FROM
  ....
  INNER JOIN (SELECT
                products_id, MIN(categories_id) min_categories_id
              FROM
                zen_products_to_categories
              GROUP BY
                products_id) min_ct
  ON pc.products_id=min_ct.products_id
     AND pc.categories_id=min_ct.min_categories_id
WHERE
  ....

Answer 2

当您与单列匹配时，子查询应该返回一列。从子查询中删除MIN(categories_id)

AND pc.products_id 
IN
(SELECT
pc.products_id
FROM
zen_products_to_categories pc
GROUP BY
pc.products_id)