摘要： 假设如下应用：两张表——用户表TDefUser（userid，address,phone）和消费表 TAccConsume(userid,time,amount)，需要查消费超过5000的用户记录。用exists:select * from TDefUserwhere exists (select 1 from TAccConsume where TDefUser.userid=TAccConsume.userid and TAccConsume.amount>5000)用in:select * from TDefUserwhere userid in (select userid fr 阅读全文