subquery in mediawiki

gistfile1.php

$select = $this->dbw->selectSQLText(                                                           
  'user_properties',                                                                         
  array( 'up_user', 'up_property', 'up_value', 'count(up_user) as count' ),                  
  'up_property=' . $this->dbw->addQuotes( $oldOption ) . ' OR up_property = ' . $this->dbw->addQuotes( $newOption ),
  __METHOD__,                                                                                
  array( 'GROUP BY' => 'up_user' )                                                           
);                                                                                             
                                                                                                       
$result = $this->dbw->select(                                                                  
  "( $select ) as user_props",                                                               
  array( 'up_user' ),                                                                        
  array( 'count' => 1 ),                                                                     
  __METHOD__                                                                                 
);