$sql = Db::name('teacher')

            ->alias('t')

            ->join('user u', 'u.user_id  = t.user_id')

            ->join('tiwen tw', 'tw.teacher_user_id = u.user_id', 'left')

            ->field([

                't.*',

                'count(if(tw.is_pingjia = 1, 1, NULL)) nu'

            ])

            ->group('u.user_id')

            ->order('count(if(tw.is_pingjia = 1, 1, null)) desc, count(tw.tiwen_id) desc')

            ->buildSql(true);

SELECT `t`.*,count(if(tw.is_pingjia = 1, 1, NULL)) nu FROM `yed_teacher` `t` INNER

JOIN `yed_user` `u` ON `u`.`user_id`=`t`.`user_id` LEFT JOIN `yed_tiwen` `tw` ON `tw`.`teacher_user_id`=`u`.`user_id`

GROUP BY `u`.`user_id` ORDER BY count(if(tw.is_pingjia = 1, 1, 0)) desc, count(tw.tiwen_id) desc