How long does business number 12 in Scottsdale stay open on day number 3?
business number refers to business_id; Scottsdale refers to city = 'Scottsdale'; day number refers to day_id;
SELECT T2.closing_time - T2.opening_time AS "hour" FROM Business AS T1 INNER JOIN Business_Hours AS T2 ON T1.business_id = T2.business_id WHERE T1.business_id = 12 AND T1.city LIKE 'Scottsdale' AND T2.day_id = 3