SQL Server does not have function which can trim leading or trailing spaces of any string. TRIM() is very popular function in many languages. SQL does have LTRIM() and RTRIM() which can trim leading and trailing spaces respectively. I was expecting SQL Server 2005 to have TRIM() function. Unfortunately, SQL Server 2005 does not have that either. I have created very simple UDF which does the same work.
FOR SQL SERVER 2000:
CREATE FUNCTION dbo.TRIM(@string VARCHAR(8000))
FOR SQL SERVER 2005/2008:
CREATE FUNCTION dbo.TRIM(@string VARCHAR(MAX))
Both the above UDF can be tested with following script
SELECT dbo.TRIM(' leading trailing ')
It will return string in result window as