You're better off using inline table-valued functions. Here's an example:
ALTER FUNCTION [dbo].[iTVF_Tester]
(@jdt_jty_code varchar(50))
RETURNS TABLE AS RETURN
SELECT ReturnValue
FROM (VALUES
('ISCO','Install'),
('ISSP','Install'),
('IECO','Install'),
('IECM','Install'),
('IESP','Install'),
('IEHD','Install'),
('ISHD','Install'),
('FRSI','Install'),
('SB42','Service Call'),
('SB4W','Service Call'),
('HD42','Service Call'),
('HD4W','Service Call'),
('SA2C','Service Call'),
('SA2W','Service Call'),
('HD2C','Service Call'),
('HD2W','Service Call'),
('SNCO','Service Call')
) x (jdt_jty_code, ReturnValue)
WHERE jdt_jty_code = @jdt_jty_code
GO
SELECT * FROM [dbo].[iTVF_Tester] ('IESP')
iTVF's behave like parameterised views. Google or search this site to find the advantages over scalar UDF's and multi-statement TVF's.
For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden