SQL group want only one of each group

Scenario: I have a product with 5 colors, 6 styles, and 7 sizes. Every color has some of every style and every size. Every style has some of every color and every size. every size has some of every color and every style. Each permutation has a unique Stock number.

I want 3 lists: group by color( 5 rows), group by style(6 rows), group by size(7 rows).

I can get the reports, correctly grouped, but I get as many rows as there are records in the file. I can not figure out how to get just the first of each group.