计总与排名SUM和RANK函数

准备一些数据：

CREATE TABLE [dbo].[SalesPerformance](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [Salesman] NVARCHAR(30) NOT NULL,
    [OrderDate] [DATE] NULL,
    [Sell]    DECIMAL(18,2) NULL
 )
GO


SELECT [Salesman],[OrderDate],[Sell] FROM [dbo].[SalesPerformance]
GO

Salesman    OrderDate    Sell
S0003    2019-05-12    23800.00
S0008    2019-05-19    66528.00
S0001    2019-05-05    35455.00
S0001    2019-05-18    75220.00
S0003    2019-05-17    33658.00
S0041    2019-05-10    56300.00
S0041    2019-05-11    41811.00
S0003    2019-05-20    26309.00
S0007    2019-05-02    41811.00
S0022    2019-05-26    26309.00
S0032    2019-05-20    20000.00
S0050    2019-05-28    20000.00

使用SUM和GROUP BY统计各个业务员的销售额：

SELECT [Salesman] AS [业务员],MONTH([OrderDate]) AS [月份], SUM([Sell]) AS [销售量]
FROM [dbo].[SalesPerformance]
GROUP BY [Salesman],MONTH([OrderDate])

然后使用RANK进行排名，看看谁是销售冠军，谁与谁同级：

;WITH [QuantityOfSale] AS
(
    SELECT [Salesman] AS [业务员],MONTH([OrderDate]) AS [月份], SUM([Sell]) AS [销售量]
    FROM [dbo].[SalesPerformance]
    GROUP BY [Salesman],MONTH([OrderDate])
)

SELECT [业务员],[月份],[销售量],RANK() OVER( ORDER BY [销售量] DESC) [销售排名]
FROM [QuantityOfSale]