Show all the locations where some cinemas were opened in year 2010
select location from cinema where openning_year = 2010
Show all the locations where some cinemas were opened in year 2011
select location from cinema where openning_year = 2011
How many locations where cinemas were opened in both year 2010 and 2011?
select count ( * ) from ( select location from cinema where openning_year = 2010 intersect select location from cinema where openning_year = 2011 )