When does Yelp_Business no.1 open on Tuesdays?
Yelp_Business no.1 refers to business_id = 1; open on refers to opening_time; Tuesdays refers to day_of_week = 'Tuesday'
SELECT T1.opening_time FROM Business_Hours AS T1 INNER JOIN Days AS T2 ON T1.day_id = T2.day_id WHERE T2.day_of_week LIKE 'Tuesday' AND T1.business_id = 1