String.IsNullOrEmpty like function for VARCHARs in SQL?

Question

Say I\'ve got a function or stored procedure that takes in several VARCHAR parameters. I\'ve gotten tired of writing SQL like this to test if these parameters have a value:

Answer 1

Use this function (based on Derek's):

CREATE FUNCTION dbo.isNullOrEmpty(@x varchar(max)) RETURNS BIT AS
BEGIN
    IF @x IS NOT NULL AND LEN(@x) > 0
        RETURN 0

    RETURN 1
END

as

dbo.isNullOrEmpty(@someVar)

or

WHERE dbo.isNullOrEmpty(@someVar) = 1

in a stored procedure or query.