title: Cast field to bit 0 if null and bit 1 if not
body: <p>I use this method to check if a row is foreign keyed in another table.</p>
  
  <pre class="lang-sql prettyprint-override"><code>select
    personID,
    name,
    (
      /* CAST THIS PART TO BIT return 1 if field is found, 0 if not */
      select top 1 parents.personID
      from parents
      where parents.personID=persons.personID
  
    ) as inUse
  from persons
  </code></pre>
  
  <p>Is it possible to do as I commented?</p>