Show the id and name of all mountains.
select id, name from mountain
Show the id and name of all the mountains that have photos.
select t1.id, t1.name from mountain as t1 join photos as t2 on t1.id = t2.mountain_id
What are the id and name of mountains that have photos and heights above 4000?
select t1.id, t1.name from mountain as t1 join photos as t2 on t1.id = t2.mountain_id where t1.height > 4000