Table schema:
CREATE TABLE CARS_DATA (Id VARCHAR, Weight INTEGER); CREATE TABLE CARS_DATA (Weight INTEGER); CREATE TABLE CAR_NAMES (model VARCHAR, MakeId VARCHAR)

Question: Find the model of the car whose weight is below the average weight.
SQL: SELECT T1.model FROM CAR_NAMES AS T1 JOIN CARS_DATA AS T2 ON T1.MakeId = T2.Id WHERE T2.Weight < (SELECT AVG(Weight) FROM CARS_DATA)