$command = Admin::find()

-> select('tbl_user.*,tbl_admin.*')

-> join('LEFT JOIN','tbl_user','tbl_user.admin_id=tbl_admin.id')

-> asArray()

-> all();

等同于

$command = ( new \yii\db\Query())

-> select('tbl_user.*,tbl_admin.*')

-> from( 'admin' )

-> join('LEFT JOIN','tbl_user','tbl_user.admin_id = tbl_admin.id')

-> asArray()

-> all();