我需要一些关于窗口函数的帮助.
我最近一直在玩sql 2012窗口函数.我知道您可以计算窗口内的总和以及窗口内的运行总和.但我在想;是否可以计算先前的运行总数,即不包括当前行的运行总数?我假设您需要使用ROW或RANGE参数,我知道有一个CURRENT ROW选项,但我需要一个CURRENT ROW – 我的语法无效.我对ROW和RANGE参数的了解是有限的,所以任何帮助都会被感激不尽.
我知道这个问题有很多解决方案,但我希望了解ROW,RANGE参数,我认为这些问题可以解决.我已经提供了一种可能的方法来计算以前的运行总量,但我想知道是否有更好的方法.
USE AdventureWorks2012 SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty,SUM(s.OrderQty) OVER (PARTITION BY SalesOrderID) AS RunningTotal,SUM(s.OrderQty) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID) - s.OrderQty AS PrevIoUsRunningTotal -- Sudo code - I know this does not work --,SUM(s.OrderQty) OVER (PARTITION BY SalesOrderID -- ORDER BY SalesOrderDetailID -- ROWS BETWEEN UNBOUNDED PRECEDING -- AND CURRENT ROW - 1) -- AS SudoCodePrevIoUsRunningTotal FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670,43669,43667,43663) ORDER BY s.SalesOrderID,s.OrderQty
提前致谢
USE AdventureWorks2012 SELECT s.SalesOrderID,s.OrderQty
解决方法
您可以减去当前行的值:
SUM(s.OrderQty) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID) - s.OrderQty
或者根据syntax at MSDN和ypercube's answer:
<window frame preceding> ::= { UNBOUNDED PRECEDING | <unsigned_value_specification> PRECEDING | CURRENT ROW }
- >
SUM(s.OrderQty) OVER (PARTITION BY SalesOrderID ORDER BY SalesOrderDetailID ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING)