How many weddings were hosted in each church?
select count(*) from church as t1 join wedding as t2 on t1.church_id = t2.church_id group by t1.church_id
Show all church names that have hosted least two weddings.
select t1.name from church as t1 join wedding as t2 on t1.church_id = t2.church_id group by t1.church_id having count(*) >= 2