Question

我有两张表如下

companyid name      
1         pwc       
2         dell      
3         microsoft 
4         google    
5         yahoo     
6         twitter   

companyid  state        month   powerconsumption

1          newyork       jan    240
2          california    jan    130    
3          arizona       jan    210
4          texas         jan    130
5          texas         jan    650
6          california    jan    310
2          arizona       jan    340

我想查询列出每个州的公司，这个州在1月份消耗了最大的权力。所以上述数据的结果将是

arizona    dell      340
california twitter   310
newyork    pwc       240
texas      yahoo     650

Answer 1

SELECT DISTINCT（SELECT name FROM company WHERE（companyid =（SELECT TOP（1）companyid FROM consumption WHERE（state = a.state）AND（month = a.month）ORDER BY powerconsumption DESC）））AS公司，州，月，（SELECT TOP（1）powerconsumption FROM consumption AS consumption_1 WHERE（state = a.state）AND（month = a.month）ORDER BY powerconsumption DESC）AS powerconsumption 来自dbo.consumption AS a

Answer 2

尝试此查询：

SELECT x.State,
    c.Name AS CompanyName,
    x.PowerConsumption
FROM
(
SELECT  pc.CompanyID, pc.State, pc.PowerConsumption,
        DENSE_RANK() OVER(PARTITION BY pc.State ORDER BY pc.PowerConsumption DESC) AS Rnk
FROM    dbo.PowerConsumptionTable pc
WHERE   pc.Month = 'jan'
) x     INNER JOIN dbo.CompanyTable c ON x.CompanyID = c.CompanyID
WHERE   x.Rnk = 1

Answer 3

我得到了答案，这对我来说似乎是最好的方式。它有一个子查询，但我没有办法避免这种情况。

选择t2.state，t1.name，t2.powerconsumption FROM table1 t1 JOIN table2 t2 ON t1.companyid = t2.companyid 其中t2.powerconsumption =（从table2 t3中选择MAX（t3.powerconsumption），其中t3.state = t2.state和t3.month ='jan'）

<强> SQL Fiddle

需要SQL查询

3 个答案: