Filtering Records in SQL Server using date

Question

I need to select all the records which are not older than 18 months. I wrote this query for SQL Server. But it don't seem to work.

SELECT DISTINCT Company, 
        Name,
        PhoneNumber,
FROM        Request
WHERE       Company  LIKE @Company
AND     RequestDate >= ADD_MONTHS(SYSDATE, -18)

Answer 1

SELECT DISTINCT Company,  
        Name, 
        PhoneNumber, 
FROM        Request 
WHERE       Company  LIKE @Company 
AND     datediff(mm, RequestDate, getdate()) <= 18

Use the DATEDIFF function for this. The above query should get you your desired results.

Answer 2

SELECT DISTINCT Company, Name, PhoneNumber, 
FROM Request WHERE Company LIKE @Company 
AND RequestDate >= DATEADD(MONTH, -18, GETDATE())