Replace null value with previous available value in Row SQL server query

Question

I am looking for building a query to replace null value with previous available values.can somebody help.Here is the table currently looking like

11/30/2015          


        

Answer 1

The below statement working perfectly

SELECT 
CASE WHEN DATE1 IS NULL 
     THEN 
(SELECT TOP 1 DATE1 FROM Table1 WHERE ID2

The output like below

        DATENEW             Date1          ID   Class      ID2
        11/30/2015          11/30/2015     ID1  ClassName   1
        11/30/2015          NULL           ID1  ClassName   2
        11/30/2015          NULL           ID1  ClassName   3
        11/30/2015          NULL           ID1  ClassName   4
        12/31/2015          12/31/2015     ID1  ClassName   5
        12/31/2015          NULL           ID1  ClassName   6
        12/31/2015          NULL           ID1  ClassName   7