SQL 查询，用于从表"中查找仅针对最大金额的所有 ID 的总计金额总和"

Question

Totals表是

ID|Amount 
1|10
1|20
2|30
2|40
3|50
4|60
5|70
5|80

尝试在下面的SQL查询中查找表Totals中所有ID的Amountsum，仅针对最大金额：

select SUM(Amount) from Totals
where ID in (select Max(ID) from Totals
group by ID
order by ID desc);

Answer 1

使用获取每个 ID 的最大数量的子查询，然后求和。

SELECT SUM(amount) as totalMax
FROM (
SELECT MAX(amount) AS amount
FROM Totals
GROUP BY ID
) AS x