aggregate-functions - where 子句和聚合函数

Question

Deposit(accno,cname,bname,amount) 问题：列出B1分行最大存款的客户名称。答：从Deposit where amount in中选择cname（select max(amount) from deposit where bname='B1'）；答案正确吗？如果不正确，请指出错误并解释正确答案。谢谢你。

Answer 1

It is correct but it will probably be slow on a large dataset and if you don't have indexes on amount and bname.

I would rather use something like

SELECT cname FROM Deposit WHERE bname='B1' ORDER BY amount DESC LIMIT 1;