title: Informix multiple joins
body: <p>I need to modify my query to add other join. But the new join probably needs to be a left join. I am unsure how to go about this. I am using Informix:</p>
  
  <pre><code>     set    query   "SELECT DISTINCT x.xfertype,x.app_type,x.service_type,x.lang,x.area_type,x.area_value,x.module,x.field1,x.field2,x.disabled,a.frames,a.allocs,a.term_id,t.term,c.center_id,c.center_name,a.message_id,x.field3,x.apn_type,x.global, a.icm, s.group_name "
      append  query   " FROM test_xfertypes AS x, test_allocation AS a, test_terms AS t, test_callcenter AS c"
      append  query   " AND a.xfertype = x.xfertype "
      append  query   " AND a.term_id = t.term_id "
      append  query   " AND t.center_id = c.center_id ";
  </code></pre>
  
  <p><code>test_xfertypes AS x</code> contains <code>area_value</code> (int)</p>
  
  <p>I want to left join the above table with another  new table <code>test_routing_groups AS s</code>.</p>
  
  <p>I want to left join such that it returns <code>s.group_name WHERE x.area_value IN (s.area_id)</code>; if the group_name exists return the group_name otherwise return null.</p>