La columna 'id' en la lista de campos es ambigua en YII

Cualquiera

cambio:$criteria->select = "username" to ==> $criteria->select = "u.username"

O

elimine:$criteria->alias = "u" and change $criteria->select = "username" to ==> $criteria->select = "t.username" and change all left join alias 'u.field_name' to ==> 't.field_name'