Table schema:
CREATE TABLE CAR_NAMES (Model VARCHAR, MakeId VARCHAR); CREATE TABLE CARS_DATA (Id VARCHAR, mpg VARCHAR)

Question: Which model saves the most gasoline? That is to say, have the maximum miles per gallon.
SQL: SELECT T1.Model FROM CAR_NAMES AS T1 JOIN CARS_DATA AS T2 ON T1.MakeId = T2.Id ORDER BY T2.mpg DESC LIMIT 1