query: SELECT count(*) ,  avg(age) ,  city_code FROM student GROUP BY city_code
question: How many students live in each city and what-all are their average age?
query_toks: SELECT count ( * ) , avg ( age ) , city_code FROM student GROUP BY city_code
query_toks_no_value: select count ( * ) , avg ( age ) , city_code from student group by city_code
question_toks: How many students live in each city and what-all are their average age?