title: Union on two tables with a where clause in the one
body: <p>Currently I have 2 tables, both of the tables have the same structure and are going to be used in a web application. the two tables are production and temp. The temp table contains one additional column called [signed up]. Currently I generate a single list using two columns that are found in each table (recno and name). Using these two fields I'm able to support my web application search function. Now what I need to do is support limiting the amount of items that can be used in the search on the second table. the reason for this is become once a person is "signed up" a similar record is created in the production table and will have its own recno.</p>
  
  <p>doing:</p>
  
  <pre><code>Select recno, name
    from production
  UNION ALL
  Select recno, name
    from temp
  </code></pre>
  
  <p>...will show me everyone. I have tried:</p>
  
  <pre><code>Select recno, name
    from production
  UNION ALL
  Select recno, name
    from temp
   WHERE signup &lt;&gt; 'Y'
  </code></pre>
  
  <p>But this returns nothing? Can anyone help?</p>