Show me all different market ids in any film market estimation.
select distinct market_id from film_market_estimation
Show me those with a low estimate above 10000.
select market_id from film_market_estimation group by market_id having max(low_estimate) > 10000
What is the average number of cities of them?
select avg(t2.number_cities) from film_market_estimation as t1 join market as t2 on t1.market_id = t2.market_id where t1.low_estimate > 10000