title: #1241 - Operand should contain 1 column(s)
body: <p>In the following query am trying to get one image per category</p>
  
  <pre><code>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 &gt;= lo.category_id
     AND l.category_id &lt;= lo.category_id
     AND l.id &gt;= lo.mid
  </code></pre>
  
  <p>but keep getting the following error :</p>
  
  <pre><code>#1241 - Operand should contain 1 column(s)
  </code></pre>
  
  <p>Any ideas ?</p>