Yii Select Query

Select Query Different Format

Select one records on Yii model: Format1
$filetype=User::model()->find('Usertype=:usertype',array(':usertype'=>'Student'));

$usermodel=User::model()->findAllByPk($userid);
$usermodel=User::model()->findByPk(1);

$usermodel=User::model()->findAllByPk($useridarray);
$usermodel=User::model()->findAllByPk(array(2,3,10));


Select Query: Format2
$model=User::model()->findAll('usertype=:usertype',array(':usertype'=>'user'));