SSRS - Matrix Table Reading Previous Row Values

问题

I've been trying to read the previous row value(that displays hourly quantities) on the matrix table to compare it with current row value and highlight the background color to yellow if the difference between them is out of accepted tolerance range.

The matrix table has a combination of grouping on column and row(for only hourly information) that is shown on the picture.

Tried to use the custom code to achieve this, but I'm getting an incorrect result .

I've attached the report design image, and result of that along with the custome code.

Please help me to figure out what is wrong on the logic.

Images: Result: Code: custom code written under report properties -> Code

Public Shared previous as Object 
Public Shared current as Object = Nothing

Public Shared Function GetCurrent(Item as Object) as Object
    previous=current
    current=Item
    return current
End Function

Public Shared Function GetPrevious()
    return previous
End Function


public Shared Function IsHourlyDiffAboveTolerance(previousValue as Integer, currentValue as Integer, variantPercent as Decimal, variantVolume as Decimal, sortOrder as Integer) As Object

    If previousValue = Nothing Then
        Return Nothing
    Else
        Dim diff as Integer
        diff = abs(currentValue - previousValue)

        Dim tolerance as decimal
        tolerance = 0.0

        If variantPercent <> 0 Then
            tolerance = previousValue * (variantPercent/100)
        Else If variantVolume <> 0 Then
            tolerance = variantVolume
        End If

        If diff >= 0 And diff <= tolerance Then
            return Nothing
        Else
            return 1
        End If
    End If
End Function

Caller Expression:

=IIF(
IsNothing(Code.IsHourlyDiffAboveTolerance(Code.GetPrevious(), Code.GetCurrent(Fields!ExpectedQty.Value), 
    Fields!VariantPercent.Value, Fields!VariantVolume.Value, Fields!SortOrder.Value)), 
"No Color", 
"Yellow")

Update: either variant volume or quantity can exist but not both.

Thanks

回答1:

I would use the new analytical function LEAD() and LAG() for SQL Server 2012. These functions access data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join. To use these functions with a matrix, you'll probably need to use PARTITION BY in the clause for the grouping.

Example SQL:

USE AdventureWorks
GO

SELECT 
      s.SalesOrderID
    , s.SalesOrderDetailID,s.OrderQty
    , LeadValue = LEAD(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID) 
    , LagValue = LAG(SalesOrderDetailID) OVER (ORDER BY SalesOrderDetailID) 
FROM 
    Sales.SalesOrderDetail s
WHERE 
    SalesOrderID IN (43670, 43669, 43667, 43663)
ORDER BY 
      s.SalesOrderID
    , s.SalesOrderDetailID
    , s.OrderQty
GO

Reference Article

来源：https://stackoverflow.com/questions/49393537/ssrs-matrix-table-reading-previous-row-values