List active business ids with opening times of 7AM and closing times of 8PM.
opening times of 7AM and closing times of 8PM refer to Business_Hours where opening_time = '7AM' and closing_time = '8PM'; active business refers to business_id where active = 'true';
SELECT DISTINCT T4.business_id FROM Categories AS T1 INNER JOIN Business_Categories AS T2 ON T1.category_id = T2.category_id INNER JOIN Business_Hours AS T3 ON T2.business_id = T3.business_id INNER JOIN Business AS T4 ON T3.business_id = T4.business_id WHERE T4.active = 'true' AND T3.opening_time = '7AM' AND T3.closing_time = '8PM'