What are the populations of the districts?
select city_population from district
Can you also tell me the stores in each district along with the population?
select t3.store_name, t1.city_population from district as t1 join store_district as t2 on t1.district_id = t2.district_id join store as t3 on t3.store_id = t2.store_id
Which of these stores are from the districts with above average population?
select t3.store_name from district as t1 join store_district as t2 on t1.district_id = t2.district_id join store as t3 on t3.store_id = t2.store_id where t1.city_population > (select avg(city_population) from district)
What about the stores from the district with the most population?
select t1.store_name from store as t1 join store_district as t2 on t1.store_id = t2.store_id where district_id = (select district_id from district order by city_population desc limit 1)