zend-framework - zend framework db limit

¿Cómo puedo unirme a una subconsulta usando Zend_Db_Select?

Question

¿Cómo construiría esta consulta usando Zend_Db_Select? :

SELECT users.user_id, email_address, t1.value as ''languages''    
FROM users
LEFT JOIN (
  SELECT
    user_id
    , field_id
    , GROUP_CONCAT(value SEPARATOR '','') AS value
  FROM user_multivalued
  WHERE field_id=25
  GROUP BY user_id, field_id) t1
ON t1.user_id = users.users_id
WHERE list_id = 45

Answer 1

$user_multivalued = $db
    ->select()
    ->from(''user_multivalued'', array(
        ''user_id'',
        ''field_id'',
        new Zend_Db_Expr("GROUP_CONCAT(value SEPARATOR '','') AS value")
    ))
    ->where(''field = ?'', 25)
    ->group(''user_id'')
    ->group(''field_id'')
;

$select = $db
    ->select()
    ->from(''users'', array(''user_id'', ''email_address''))
    ->joinLeft(
        array(''t1'' => $user_multivalued),
        ''t1.user_id = users.user_id'',
        array(''languages''=>''value'')
    )
    ->where(''list_id = ?'', 45)
;