Question

我有下表：

ClientId | CalculationDate | TransactedAmount |
  1         13/02/2015              3
  1         14/02/2015              3
  2         14/02/2015              5
  3         15/03/2015              6
  2         15/03/2015              5

因此，我想要包含ClientId的表和从那时起传递的最小月数每个clientId交易最大金额。我怎么能这样做？

Answer 1

   SELECT DISTINCT ClientId , MaxAmount.TransactedAmount , DATEDIFF(MONTH,MaxAmount.CalculationDate ,getdate())
   FROM TABLENAME T1
        CROSS APPLY(SELECT TOP 1 TransactedAmount ,CalculationDate 
                    FROM TABLENAME T2
                    WHERE  T1.ClientId = T2.ClientId 
                    ORDER BY TransactedAmount DESC) MaxAmount

Answer 2

使用像Row_Nummber（）这样的Window函数我们可以实现相同的

;With cte(ClientId , CalculationDate , TransactedAmount )
AS
(
SELECT 1,'13/02/2015',3 UNION ALL
SELECT 1,'14/02/2015',3 UNION ALL
SELECT 2,'14/02/2015',5 UNION ALL
SELECT 3,'15/03/2015',6 UNION ALL
SELECT 2,'15/03/2015',5 
)
SELECT ClientId , CalculationDate,TransactedAmount From
(
SELECT ClientId , CalculationDate ,MAX(TransactedAmount)OVER(Partition by ClientId Order by  CalculationDate) As TransactedAmount ,
ROW_NUMBER()OVER(Partition by ClientId Order by  CalculationDate) AS RNo From cte
)Dt 
WHERE Dt.RNo=1

从相应的日期中选择最大值和最小日期

2 个答案: