Database: real_estate_rentals
Question: On average, how many rooms do properties with garden features have?
SQL:
SELECT avg(T3.room_count) FROM Property_Features AS T1 JOIN Features AS T2 ON T1.feature_id  =  T2.feature_id JOIN Properties AS T3 ON T1.property_id  =  T3.property_id WHERE T2.feature_name  =  'garden';