Access中模块的程序如下，现在想在SQL中实现。主要是不知道这个循环判断逻辑怎么用SQL语言实现。求大神帮忙啊～～～

Private Sub UpdateReSA()

  DimTable_SA

  Dimcount As Long

  Dimi As Long

  DimInsured(Num) As String

  DimRetain(Num) As Double

  DimAvailableRetain(Num) As Double

   

  SetTable_SA = CurrentDb.OpenRecordset("20 SA")

  

count = Table_SA.RecordCount

Table_SA.MoveFirst

Insured(0) = 0

Retain(0) = 0

AvailableRetain(0) = Table_SA.可用自留额

For i = 1 To count

'Do While Not Table_SA.EOF

Table_SA.Edit

   

Insured(i) = Table_SA.INSURED_ID

   If Insured(i) = Insured(i - 1) Then

       Table_SA.可用自留额 = Max(AvailableRetain(i - 1) - Retain(i - 1), 0)

   Else

   End If

   If Table_SA.已分出标记 = 0 And Table_SA.分保类型 = "Auto" Then

  

       Table_SA.自留额 = Min(Table_SA.风险保额 * Table_SA.合同成数, Table_SA.可用自留额)            

   Else

       Table_SA.自留额 = Table_SA.风险保额 * (1 - Table_SA.分出比例)

   End If

   Table_SA.分出额 = Table_SA.风险保额 - Table_SA.自留额

   

   Retain(i) = Table_SA.自留额

   AvailableRetain(i) = Table_SA.可用自留额

   Table_SA.Update

   Table_SA.MoveNext

'Loop  Next    Table_SA.Close    MsgBox "Finish！"     End Sub