Using select expressions or derived field in Views2 as fields?
It looks like what I need to do is create a Custom Field Handler. From the linked article, a definition such as this

&lt;?php
class scheduler_handler_field_scheduler_countdown extends views_handler_field {
  function query() {
    $this-&gt;ensure_my_table();
    $this-&gt;node_table = $this-&gt;query-&gt;ensure_table('node', $this-&gt;relationship);
    $this-&gt;field_alias = $this-&gt;query-&gt;add_field(NULL,
      'IF(publish_on AND publish_on &gt; UNIX_TIMESTAMP(),
        publish_on - UNIX_TIMESTAMP(), NULL)',
      $this-&gt;table_alias . '_' . $this-&gt;field);
  }
}
?&gt;


adds this to the query

SELECT node.nid AS nid,
       node.title AS node_title,
       IF(publish_on AND publish_on &gt; UNIX_TIMESTAMP(),
           publish_on - UNIX_TIMESTAMP(),
           NULL) AS scheduler_publish_countdown
    FROM node node
    LEFT JOIN scheduler scheduler ON node.nid = scheduler.nid
    WHERE node.status = 0