What are the restaurants that are located at "19th St. Oakland"?
restaurant refers to label; "19th St. Oakland" refers to street_name = '19th St' AND city = 'Oakland'
SELECT T1.id_restaurant FROM generalinfo AS T1 INNER JOIN location AS T2 ON T1.id_restaurant = T2.id_restaurant WHERE T1.city = 'Oakland' AND T2.street_name = '19th St'