Gender    Generation    Sales
Male      Baby Boomer   30
Male      Silent Gen.   40
Female    Baby Boomer   70
Female    Silent Gen.   20

with Gendertbl AS
(SELECT DISTINCT Gender FROM sampletable UNION select '' from sampletable),
with Generationtbl AS
(SELECT DISTINCT Generation from sampletable UNION select '' from sample table)

SELECT G1.Gender, G2.Generation
FROM sampletable G1
CROSS JOIN sampletable G2

Gender    Generation
Male
Male      Baby Boomer
Male      Silent Gen.
Female
Female    Baby Boomer
Female    Silent Gen.

Gender    Generation    Sales
Male                    100
Male      Baby Boomer   30
Male      Silent Gen.   40
Female                  200
Female    Baby Boomer   70
Female    Silent Gen.   90