Database: real_estate_rentals
Question: What is the total max price of the properties owned by single mothers or students?
SQL:
SELECT sum(T1.price_max) FROM Properties AS T1 JOIN Users AS T2 ON T1.owner_user_id  =  T2.user_id WHERE T2.user_category_code  =  'Single Mother' OR T2.user_category_code  =  'Student';