Show me all the companies.
select name from operate_company
Which of these companies operate flights?
select distinct name from operate_company as t1 join flight as t2 on t1.id = t2.company_id
Which companies operated flights with velocity less than 200?
select distinct name from operate_company as t1 join flight as t2 on t1.id = t2.company_id where t2.velocity < 200
What are the distinct types of these companies?
select distinct t1.type from operate_company as t1 join flight as t2 on t1.id = t2.company_id where t2.velocity < 200