title: Updating column on one table with values from another table
body: <p>I'm trying to update an empty table notes, with values that come from a column in another table deals:</p>
  
  <pre><code>UPDATE notes
  SET notes.content = (
  SELECT deals.memo
  FROM deals
  WHERE deals.id = notes.deal_id
  );
  </code></pre>
  
  <p>this runs with no error but no notes get updated although there are loads of values in memo. </p>
  
  <p>There's no values at all in notes. Can this be the problem?</p>