SELECT membership_card FROM member WHERE address  =  'Hartford' INTERSECT SELECT membership_card FROM member WHERE address  =  'Waterbury'
What is the membership card held by both members living in Hartford and ones living in Waterbury address?
SELECT membership_card FROM member WHERE address = 'Hartford ' INTERSECT SELECT membership_card FROM member WHERE address = 'Waterbury '
select membership_card from member where address = value intersect select membership_card from member where address = value
What is the membership card held by both members living in Hartford and ones living in Waterbury address ?