Can SQL Server Return A 0 (zero) When No Records Are Found?

Can someone help to fix this query so that it returns a 0 (zero), as opposed to a blank or null value, when case_id # 1049 record is not found. And if the record is indeed found it should return the case ID (numeric value).

SELECT CASE
WHEN count(*) = 0 THEN 0
ELSE a.CASE_ID
END
FROM (SELECT CASE_ID FROM CASE_DETAIL WHERE CASE_ID = 1049) a
GROUP BY CASE_ID
GO

Thank you in advance!