Взятие предыдущего значения, если Null

Declare @From date
Declare @To date
set @From = '2018-11-12'
set @To = '2018-11-26'
 
SELECT 
    DayList,
    CurrencyValue,
    LAG(CurrencyValue) OVER ( Order By DayList)
 FROM Quotes Q 
Right JOIN (
    SELECT DATEADD(d, number, @from) DayList 
        FROM numbers
    Where DATEADD(d, number, @from) Between @From AND @To
) t on Q.Day = t.DayList
Order By DayList

SELECT 
    DayList,
    isnull(CurrencyValue,
        (Select Top 1 qq.CurrencyValue 
         From Quotes qq 
         WHERE qq.Day <= DayList 
         Order By qq.Day DESC)) ShiftCurrency
FROM Quotes Q 
Right JOIN (
    SELECT DATEADD(d, number, @from) DayList 
        FROM numbers
    Where DATEADD(d, number, @from) Between @From AND @To
) t on Q.Day = t.DayList
Order By DayList

SELECT tt.DayList, CurrencyValue FROM Quotes QQ
JOIN (
SELECT 
    t.DayList,
    MAX(Q.Day) Over (Order BY DayList Range Unbounded Preceding) r
FROM Quotes Q 
Right JOIN (
    SELECT DATEADD(d, number, @from) DayList 
        FROM numbers
    Where DATEADD(d, number, @from) Between @From AND @To
) t on Q.Day = t.DayList
) tt on QQ.Day = tt.r
Order By tt.DayList