Need Help in SQL Query

Hi All:
I am new SQL Programming and i need help in doing following task.
I want to write a script that does following thing:
--If the date is 11/12/2009 or 11/12/2020 or greater than today's date than display 'D'
-- If the date is valid date other than 'D' than disply 'W',
-- If the date is blank display '' ( blank'.
Please help me in this query. Thanks all.

CASE suits your solution better, I think you have typo in question, 1st case is about BETWEEN the specified dates.CREATE
TABLE DateTable(DateCol VARCHAR(50)
)INSERT
INTO DateTable VALUES (GETDATE())INSERT
INTO DateTable VALUES (GETDATE()+4000)INSERT
INTO DateTable VALUES (GETDATE()+40000)INSERT
INTO DateTable VALUES (NULL)INSERT
INTO DateTable VALUES ('')INSERT INTO DateTable VALUES (' ')
SELECT

CASE

WHEN ISDATE(DateCol) = 1 AND CAST(DateCol AS DATETIME) BETWEEN '2009-11-12' AND '2020-11-12' THEN 'D'
WHEN ISDATE(DateCol) = 1 THEN 'W'
WHEN ISNULL(DateCol, '') = '' THEN '(BLANK)'

END AS Date

FROM DateTable

Thank you and it did work.