php - Yii sql generation -

i trying prepare following sql query unfortunately did not work.

select course.course_name, enroll.start_date dp_courses course left outer join dp_enroll enroll on course.id = enroll.course_id , enroll.student_id=3  $criteria=new cdbcriteria(array(             'order'=>'update_time desc',             'with'=> array('enroll'),         ));     $criteria->alias = 'course';     $criteria->together=true;     $criteria->join='left outer join dp_enroll on dp_enroll.course_id=course.id , dp_enroll.student_id='. yii::app()->user->id;             //$criteria->condition='dp_enroll.student_id='. yii::app()->user->id; 

relation in course model is:

 public function relations()    {      return array(                     'enroll'=> array(self::has_many, 'enroll', 'course_id'),                     'author' => array(self::belongs_to, 'yumprofile', 'author_id'),         );  } 

but resulting sql query want

left outer join dp_enroll enroll on course.id = enroll.course_id **and** enroll.student_id=3 

joining tables on 2 attribute and operator

it in docs, point 1 declaring relationship. yii not have idea composite join in example. if want join this, have define composite key relation, instad course_id define array stated in docs:

array('fk_c1'=>'pk_c1','fk_c2'=>'pk_c2')