Which browsers have market share greater than 15?
select name from browser where market_share > 15
Which of those are compatible with some accelerator?
select name from browser where market_share > 15 and id in (select browser_id from accelerator_compatible_browser)
What distinct accelerator names are compatible with the browswers that have market share higher than 15?
select distinct t1.name from web_client_accelerator as t1 join accelerator_compatible_browser as t2 on t2.accelerator_id = t1.id join browser as t3 on t2.browser_id = t3.id where t3.market_share > 15;