title: Subquery returned more than 1 value. by using 2 subquery's and subtracting them
body: <p>I'm trying to subtract 2 subquery's and then get the answer from that to show in my select statement</p>
  
  <p>I did not find any tuturials or other forum posts that could help my problem</p>
  
  <pre><code>DECLARE @Year int
  set @Year = 2018
  SET @Verloop = 12
  SELECT Lijst.positie as [Positie], titel as [Titel], Lijst.top2000jaar as [Jaar]
  , Artiest.naam as [Artiest], Verloop = (SELECT positie
  FROM Lijst
  WHERE top2000jaar LIKE @Year)-(SELECT positie
  FROM Lijst
  WHERE top2000jaar LIKE @Year -1)
  FROM Song
  INNER JOIN Lijst ON Song.songid = Lijst.songid
  INNER JOIN Artiest ON Song.artiestid = Artiest.artiestid
  WHERE Lijst.top2000jaar LIKE @Year
  </code></pre>
  
  <p>I got this error message:</p>
  
  <blockquote>
    <p>Msg 512, Level 16, State 1, Line 5
    Subquery returned more than 1 value. This is not permitted when the subquery >follows =, !=, &lt;, &lt;= , >, >= or when the subquery is used as an expression.</p>
  </blockquote>