CREATE TABLE _test(
[name] NVARCHAR(50),
related_name NVARCHAR(50)
)
GO

INSERT INTO dbo._test
([name], related_name)
VALUES

('a', 'b'),
('b', 'c'),
('c', 'd'),
('e', 'f'),
('f', 'g')

select * from my_func('a')

result
------
a
b
c
d

select * from my_func('e')

result
------
e
f
g