Salary Level Function ( T-SQL )

CREATE FUNCTION ufn_GetSalaryLevel (@salary DECIMAL(18,4))
RETURNS varchar(10) AS
BEGIN
  DECLARE @SalaryLevel VARCHAR(10)
  SET @SalaryLevel =
    CASE
    WHEN @salary < 30000 THEN 'Low'
    WHEN @salary > 50000 THEN 'High'
    ELSE 'Average'
     END
    RETURN @SalaryLevel
END;

SELECT Salary, dbo.ufn_GetSalaryLevel(Salary) AS [Salary Level]
FROM Employees
GO