如何编写查询以查找两行数量之间的差异

Question

我有这样的表格，我希望如下所述实现

EffectiveStartDate  PayElementCode           ElementAmount
04/01/2013           Basic                        14534
04/01/2013           HRA                           5814
04/01/2013           Education Allowance            200
04/01/2013           Special Allowance             2075
04/01/2013           Transportation Allowance       800
04/01/2013           Helper Allowance              3500
04/01/2013           Uniform Allowance              750
04/01/2013           LTA / LTC                     2083
04/01/2013           Medical Exp.                  1250

04/01/2014           Helper Allowance              3500
04/01/2014           Medical Exp.                  1250
04/01/2014           Tel & Mobile Exp.              600
04/01/2014           Petrol Running & Repairs      2500
04/01/2014           Attire Purchase               1667
04/01/2014           LTA / LTC                     2083

如何实现以下输出写入查询。

EffectiveStartDate  Amount      DiffAmount
2013-04-01          36335.00       0
2014-04-01          44085.00    7750

Answer 1

我实现了

;WITH CTE AS ( SELECT rownum = ROW_NUMBER() OVER (ORDER BY p.EffectiveStartDate),MONTH(p.EffectiveStartDate) as MM,YEAR(p.EffectiveStartDate) as YY, SUM(p.ElementAmount) as Salary,p.EffectiveStartDate as EffectiveDate,p.EmployeeID as EmployeeId FROM tbl_EmployeePayElement p where EmployeeID=@EmployeeId and ISSalary=1 Group By EffectiveStartDate,EmployeeID ) SELECT CTE.EmployeeId, CTE.EffectiveDate, CTE.MM,CTE.YY, CTE.Salary,ISNULL(CTE.Salary-prev.Salary,0) as Diff FROM CTE LEFT JOIN CTE prev ON prev.rownum = CTE.rownum - 1 LEFT JOIN CTE nex ON nex.rownum = CTE.rownum + 1