title: SQL Select Based on SUBSTR of Another Query
body: <p>I have a select command using substr which returns a list of numbers:</p>
  
  <p><code>select substr(numbers,76,8) as num from numtab;</code></p>
  
  <p>but when I try and run the following command to display records containing num in another table, I get 'single-row subquery returns more than one row'</p>
  
  <pre><code>select names from namtab where FK_number = (select substr(numbers,76,8) as num from numtab);
  </code></pre>