CREATE TABLE purchase (member_id DECIMAL, branch_id TEXT, year TEXT, total_pounds DECIMAL)
CREATE TABLE membership_register_branch (member_id DECIMAL, branch_id TEXT, register_year TEXT)
CREATE TABLE member (member_id DECIMAL, card_number TEXT, name TEXT, hometown TEXT, level DECIMAL)
CREATE TABLE branch (branch_id DECIMAL, name TEXT, open_year TEXT, address_road TEXT, city TEXT, membership_amount TEXT)

Show minimum and maximum amount of memberships for all branches opened in 2011 or located at city London.
SELECT MIN(membership_amount), MAX(membership_amount) FROM branch WHERE open_year = 2011 OR city = 'London'
SELECT MIN("membership_amount"), MAX("membership_amount") FROM "branch" WHERE "city" = 'London' OR "open_year" = 2011