Come gestire più "valido dopo {data}" in modo performante

Lavoriamo su un'applicazione che visualizza un elenco di ruoli e anche altre cose correlate a DateTime.

Quindi il mio database è pieno di relazioni come in questo piccolo esempio:

Ne risulta un grande StoredProcedure per ottenere tutti i dati dei dipendenti e i relativi dati relativi alla data per una determinata combinazione di dipendente, giorno, mese, anno

che appare come questo (basato sull'Esempio):

ALTER PROCEDURE Mitarbeiter_Select

    @myDate         AS datetime2(7) = null, -- null represent current
    @EmployeeId     AS int          = null  -- null represents all Employees

AS
    -- declare my intern parameters
    DECLARE @oldDate                AS datetime2(7)= null;  

    SET @Wann   = ISNULL(@Wann,GETDATE());

    -- set the previous month
    SET @oldDate= DATEADD(month, -1, @Wann); -- for some calculations i need information from the month before


    --############################# REGION TEMP TABLE ###########################
    -- create my TempTable
    create table #EmployeeToFind
    (
        ID int, 
        FirstName nvarchar(MAX), 
        LastName nvarchar(MAX)        
    )

    create table #EmployeeVacationDays
    (
        RefEmployeeId int, 
        YearDays int
    )

    create table #EmployeeManager
    (
        RefEmployeeId int, 
        IsManager bit
    )


    --############################# REGION FILL TABLE ###########################

    INSERT INTO #EmployeeToFind
    SELECT  ID, 
            Personalnummer, 
            FirstName , 
            LastName 
    FROM    Employee
    WHERE   ID = ISNULL(@EmployeeId, ID)

    INSERT INTO #EmployeeVacationDays
    SELECT  RefEmployeeId , 
            Days AS YearDays 
    FROM    VacationDays OUTERMU
    WHERE   RefEmployeeId = ISNULL(@EmployeeId, RefEmployeeId )
    AND     ValidAfter =    (
                                    SELECT  MAX(ValidAfter )
                                    FROM    VacationDays
                                    WHERE   RefEmployeeId = OUTERMU.RefEmployeeId 
                                    AND     (   YEAR(ValidAfter) = YEAR(@Wann) 
                                                OR      
                                                YEAR(ValidAfter) < YEAR(@Wann)
                                            )
                            )

    INSERT INTO #EmployeeManager
    SELECT  RefEmployeeId , 
            IsManager 
    FROM    Manager
    WHERE   RefEmployeeId = ISNULL(@EmployeeId, RefEmployeeId )
    AND     ValidAfter =    (
                                    SELECT  MAX(ValidAfter )
                                    FROM    Manager
                                    WHERE   RefEmployeeId = OUTERMA.RefEmployeeId 
                                    AND     (   YEAR(ValidAfter) = YEAR(@Wann) AND  MONTH(ValidAfter)  <= MONTH(@Wann)
                                                OR      
                                                YEAR(ValidAfter) < YEAR(@Wann)
                                            )
                            )


    --############################# REGION RESULT SELECT ###########################
    SELECT  #EmployeeToFind.ID, 
            #EmployeeToFind.FirstName , 
            #EmployeeToFind.LastName , 
            #EmployeeVacationDays.YearDays ,
            #EmployeeManager.IsManager ,

    -- in our real Procedure we have here also some CASE WHEN ... THEN ... ELSE ... END
    -- Depending on IS NULL/ IS NOT NULL of some Values

    FROM #EmployeeToFind
    left outer join #EmployeeVacationDayson #EmployeeToFind.ID= #EmployeeVacationDays.RefEmployeeId 
    left outer join #EmployeeManageron #EmployeeToFind.ID= #EmployeeManager.RefEmployeeId 

Ora la mia domanda è un modo per semplificare questo?