title: postgres condition trigger missing from clause
body: <p>I'm trying to create a trigger on my table such that it only runs if the 'prepaid' column is true for rows where I've modified the value of the 'points_per_month' column.  I tried this:</p>
  
  <pre><code>CREATE TRIGGER "fix_usage_trigger" 
  AFTER UPDATE OF "points_per_month"
  ON "public"."clients"
  FOR EACH ROW WHEN (ROW.prepaid)
  EXECUTE PROCEDURE "fix_prepaid_client_available_usage"();
  </code></pre>
  
  <p>psql is telling me this:</p>
  
  <blockquote>
    <p>ERROR:  missing FROM-clause entry for table "row"
    LINE 1: ...r_month" ON "public"."clients" FOR EACH ROW WHEN (ROW.prepai...</p>
  </blockquote>
  
  <p>Clearly I have no FROM clause there, but I'm not sure why I'd need one, nor where to put it.</p>