UFN_SALESORDER_BETWEENDATES

CREATE function dbo.UFN_SALESORDER_BETWEENDATES(@FROMDATE as date, @TODATE as date)
returns table
as return

    select
        SALESORDERS.ID
    from (
        select SALESORDER.ID, FT.CALCULATEDDATE as DATE
        from dbo.SALESORDER
        inner join dbo.FINANCIALTRANSACTION as FT on FT.ID = SALESORDER.REVENUEID

        union all
        select ID, cast(TRANSACTIONDATE as date) as DATE
        from dbo.SALESORDER
        where SALESORDER.REVENUEID is null
    ) as SALESORDERS
    where
        (@FROMDATE is null or SALESORDERS.DATE >= @FROMDATE)
        and (@TODATE is null or SALESORDERS.DATE <= @TODATE)