title: SQL : ERROR: more than one row returned by a subquery used as an expression
body: <p>The thing is that it does return one row.</p>
  
  <p>Here's the thing.</p>
  
  <pre><code>SELECT...
  
  FROM...
  
  WHERE...
  
  GROUP BY...
  
  HAVING randomNumber &gt; (SELECT value FROM.....)
  </code></pre>
  
  <p>Whenever I have signs such as =, >  it always returns me this error. When I do IN it doesn't.</p>
  
  <p>Are you not supposed to use comparison signs when comparing to another table?</p>