#1241 - 操作数应包含1列

Question

在以下查询中,我尝试为每个类别获取一个图像

SELECT  l.*
FROM    (
   SELECT  id AS category_id,
           COALESCE(
           (
           SELECT  *
           FROM    images li
           WHERE li.category_id = dlo.id

           ORDER BY
                       li.save_status DESC, li.category_id DESC, li.id DESC
           LIMIT 1
           ), 0) AS mid
   FROM    cats_imgs dlo where id='1'
   ) lo
JOIN    images l
ON      l.save_status = '3'
   AND l.category_id >= lo.category_id
   AND l.category_id <= lo.category_id
   AND l.id >= lo.mid

但不断收到以下错误:

#1241 - Operand should contain 1 column(s)

有任何想法吗 ？

Answer 1

替换*为单列images li