Typeorm

在typeorm里orderby 使用 coalesce 函数

const q = this.announcementRepository.createQueryBuilder(
            'announcement',
);

q.orderBy(`COALESCE(announcement.scheduled_at, announcement.updated_at, announcement.created_at)`, 'DESC')
//这么写 会报错 "COALESCE(`announcement" alias was not found. Maybe you forgot to join it?

//要先addselect 添加alias 然后 
q.orderBy(`COALESCE(announcement_scheduled_at, announcement_updated_at, announcement_created_at)`, 'DESC')

真的是无语了,为啥typeorm 连个orderByBaw的方法都没有,自带的raw方法返回的是FindOperator???