Question

我的SQL代码如下：

Select Model,Max(Price) FROM Printer GROUP BY Model ORDER BY Max(Price) DESC;

它应该返回以下内容：

MODEL   MAX PRICE
3007    899
3003    899

但是，它会返回：

MODEL   MAX PRICE
3007    899
3003    899
3002    139
3004    120
3006    100
3005    99

我做错了什么？我尝试更改或删除Order by等，但它并没有解决我的问题。

Answer 1

如果您只想要最高价格的行，那么您需要限制行数。您似乎想要rank()：

SELECT Model, max_price
FROM (SELECT Model, MAX(Price) as max_price,
             RANK() OVER (ORDER BY MAX(PRICE) DESC NULLS LAST) as seqnum
      FROM Printer p
      GROUP BY Model
     ) p
WHERE seqnum = 1;

Answer 2

这是一种更清洁的方法来获得我想要的东西

SELECT 
Model, 
Price
FROM
Printer
WHERE price = (SELECT MAX(PRICE) FROM Printer)
;

Answer 3

如果您使用的是Oracle 12.1或更高版本：

select model, max(price) from printer
group by model
order by max(price) desc
fetch first row with ties;

SQL：Max Value未选择Max

3 个答案: