开窗函数 SUM() OVER()

 1 DECLARE @Temp Table
 2 (
 3   ID INT, --- 月份
 4   MoneyData Float  --- 金额 
 5 )
 6  
 7 insert  INTO @TEMP
 8 SELECT 1,100 UNION ALL
 9 SELECT  2,200 UNION ALL
10 SELECT  3,300 UNION ALL
11 SELECT  4,400 UNION ALL
12 SELECT  5,500 UNION ALL
13 SELECT  6,600 UNION ALL
14 SELECT  7,600

1 SELECT  A.ID, SUM(B.MoneyData)  FROM @Temp A INNER JOIN @Temp B
2 ON A.ID>=B.ID GROUP BY A.ID
3 ---- 重点在于 ON 条件，通过自连接 A.ID >= B.ID ，可获取所需数据，再通过GROUP BY 、SUM 即可统计求和

1 SELECT  ID, MoneyData,   SUM(MoneyData) OVER( ) AS ‘总销售额‘,
2 SUM(MoneyData) OVER( PARTITION BY ID ) AS ‘月销售额‘,
3 SUM(MoneyData) OVER( ORDER BY ID ASC)  AS ‘当月+当月前销售额‘
4 FROM @Temp
5 ---- 此处，使用开窗函数使用更为简单，不过，其中 SUM() OVER ( ORDER BY ID ASC ) 即可实现以上功能