I haven't found a way to use subqueries as alias with criteria in the book.

Here is a small piece of code that works very well:

the subquery is in an alias defined by Criteria::addAsColumn($alias, $expr)

it can be used to order the result, or in case you have to deal with foreign keys, etc.

$c = new Criteria();
 
$c->addAsColumn('brandname', '(SELECT brand.name FROM brand WHERE brand.id=brand_id)');
 
$c->addAscendingOrderByColumn($c->getColumnForAs('brandname'));
 
$this->products = ProductPeer::doSelect($c);
 

Product has a brand_id that references the id key of the brand table that contains the 'name' field which is used to order the result.

Patrice Blanchardie