将列除以特定员工的另一列

Question

我有一张这样的表：

 [MS_EmployeeNumber]  [MS_Semel] [MS_Month] [MS_Amount]
      2222                400         1          20
      2222                154         1          40
      2222                 10         1          14
      2222               3000         1          120
      3333               400          1           20
      3333                154         1          232
      3333               3000         1          150
      4444                14          1          124

我想创建一个这样的表（没有计算课程）

[MS_EmployeeNumber] [MS_Semel] JanAmount FromBrutoJan   FebAmount ...
2222                   400         20       0.16=20/120
2222                   154         40       0.33=40/120
.
.
3333                   400         20       0.13 = 20/150  
3333                   3000        150       1=150/150
4444                    14         124          NA

我开始写这个：

select
ROW_NUMBER()  OVER (ORDER BY  [MS_EmployeeNumber]) AS Row,
  [MS_EmployeeNumber],
  [MS_Semel],
  sum(case when [MS_Month] in (1) then [MS_Amount] else 0 end) as JanAmount,
   sum(case when [MS_Month] in (1) then [MS_Amount] else 0 end) /NULLIF((sum(case when [MS_Month] in (1) And [MS_Semel] = '3000' then [MS_Amount] else 0 end)),0) as SmlFromBruto,
  sum(case when [MS_Month] in (2) then [MS_Amount] else 0 end) as FebAmount,
  sum(case when [MS_Month] in (3) then [MS_Amount] else 0 end) as MarAmount,
  sum(case when [MS_Month] in (4) then [MS_Amount] else 0 end) as AprAmount,
  sum(case when [MS_Month] in (5) then [MS_Amount] else 0 end) as MayAmount,
  sum(case when [MS_Month] in (6) then [MS_Amount] else 0 end) as JuneAmount,
  sum(case when [MS_Month] in (7) then [MS_Amount] else 0 end) as JulAmount,
  sum(case when [MS_Month] in (8) then [MS_Amount] else 0 end) as AugAmount
from [dbo].[MonthlySalary] where [MS_MSF_Code] between 4 and 27 
group by MS_EmployeeNumber,MS_Semel
order by MS_EmployeeNumber, MS_Semel 

我真的希望你能帮助我们为每个员工创建一个偏差列。 [MS_Semel]根据他的 Bruto [MS_Semel = 3000]，参见示例。 我bruto为null将其设置为零（请参阅nullif），如果不是[MS_Semel] = 3000，则员工不是exsit将其设置为'NA'。