title: Query referencing another query
body: <p>I can't execute a query in Power Query and the error that throws me is like:  </p>
  
  <blockquote>
    <p>Formula.Firewall: Query XXX references other queries or steps, so it may not directly access a data source. Please rebuild this data combination.</p>
  </blockquote>
  
  <p>The code within this query is as below:</p>
  
  <pre><code>let
      CallToFunction = myFunction,
      #"Invoked Function" = CallToFunction(),
      Source = Oracle.Database("myServer", [Query="SELECT * FROM myTable WHERE CustomerPK IN (" &amp; #"Invoked Function" &amp; ")"])
  in
      Source
  </code></pre>
  
  <p><code>myFunction</code> is a function that uses a couple of other queries and eventually returns a string of primary keys that I can use to fill in the parenthesis of the WHERE clause of my SQL statement.</p>
  
  <p>When I invoke the function alone it works correctly, so this must be an issue of how to call the function within the last query.  </p>
  
  <p>Any ideas?</p>