What are the id and address of the shops which have a happy hour in May?
SELECT t1.address ,  t1.shop_id FROM shop AS t1 JOIN happy_hour AS t2 ON t1.shop_id  =  t2.shop_id WHERE MONTH  =  'May'
shops which have a happy hour in May refers to the join condition on shop_id between shop and happy_hour tables where the MONTH = 'May'; id and address of the shops refers to t1.shop_id and t1.address;