title: Informix: Select null problem
body: <p>Using Informix, I've created a tempory table which I am trying to populate from a select statement. After this, I want to do an update, to populate more fields in the tempory table.</p>
  
  <p>So I'm doing something like;</p>
  
  <pre><code>create temp table _results (group_ser int, item_ser int, restype char(4));
  
  insert into _results (group_ser, item_ser)
  select 
        group_ser, item_ser, null
  from
        sometable
  </code></pre>
  
  <p>But you can't select null.</p>
  
  <p>For example;</p>
  
  <pre><code>select first 1 current from systables
  </code></pre>
  
  <p>works but</p>
  
  <pre><code>select first 1 null from systables
  </code></pre>
  
  <p>fails! </p>
  
  <p>(Don't get me started on why I can't just do a SQL Server like "select current" with no table specified!)</p>