title: mysql union different number of columns
body: <p>I know union queries have to have the same number of columns.  I'm trying to get results from the table <code>comments</code> and results from the table <code>strings</code>, which has multiple joins.  How do i this correctly?  I haven't tested yet because i know i'll get an error with different number of columns.  Here are the two queries that i'm trying to combine.</p>
  
  <p>query 1(strings)</p>
  
  <pre><code>SELECT sub.actionid as usersub, 
                  ftable.`last-time` as lastvisited, updatetable.recent as mostrecent, parent.* FROM `strings` as parent 
          LEFT JOIN subscribe sub on sub.actionid=parent.id AND sub.userid=:userid
          JOIN followers ftable on ((ftable.sid=parent.sid AND ftable.page='1') OR 
          (ftable.sid=parent.sid AND ftable.position=parent.position AND ftable.page='0') 
          OR (ftable.profile=parent.starter AND parent.guideline='1')) AND ftable.userid=:userid
          JOIN `update-recent` updatetable on 
          ((updatetable.sid=parent.sid AND updatetable.position=parent.position AND updatetable.pageid='0')
          OR (updatetable.profile=parent.starter) OR (updatetable.pageid=parent.pageid AND parent.pageid!=0))
          WHERE ftable.userid=:userid AND parent.deleted='0' GROUP BY parent.id 
  </code></pre>
  
  <p>query 2(comments)</p>
  
  <pre><code>SELECT * FROM comments WHERE viewed='0' AND (`starter-id`=:userid OR respondid=:userid)
  </code></pre>
  
  <p>I'd like to order the results by the timestamp column <code>posted</code> (most recent) <code>ORDER BY posted DESC</code></p>
  
  <p>How do i union these queries?</p>