title: Only one expression can be specified in the select list when the subquery is not introduced with EXISTS
body: <p>My query is as follows, and contains a subquery within it:</p>
  <pre><code> select count(distinct dNum)
   from myDB.dbo.AQ
   where A_ID in 
    (SELECT DISTINCT TOP (0.1) PERCENT A_ID, 
              COUNT(DISTINCT dNum) AS ud 
   FROM         myDB.dbo.AQ
   WHERE     M &gt; 1 and B = 0 
   GROUP BY A_ID ORDER BY ud DESC)
  </code></pre>
  <p>The error I am receiving is ...</p>
  <blockquote>
  <p>Only one expression can be specified in the select list when the subquery is not
  introduced with EXISTS.`</p>
  </blockquote>
  <p>When I run the sub-query alone, it returns just fine, so I am assuming there is some issue with the main query?</p>