Question

sql语句查询入门问题

select [branch-name],avg(balance)
from Account
group by [branch-name]
having avg(balance)>500

上面这句正确，可是在末尾加上：

order by balance asc

后就不正确了

Answer 1

看清楚了！

avg(balance) ：这个地方没有别名，所以sql找不到balance

你可以帮他添加一个别名

avg(balance) as balance

你试试看
select [branch-name],avg(balance) as balance
from Account
group by [branch-name]
having avg(balance)>500
order by balance asc
有问题请告知！

Answer 2

当你在sql语句中用了含有group by 关键字时，后面的要再使用order by 关键字时，排序的列必须是显示出来的列，也就是在select 后面要能找得到的列。

你可以这样试下：
select [branch-name],avg(balance)，balance
from Account
group by [branch-name]
having avg(balance)>500
order by balance asc

Answer 3

我想数据库强者的 答案是正确的。balance是一个汇总的值，不能进行Order的