query: SELECT sum(stu_hrs) ,  dept_code FROM student GROUP BY dept_code
question: Find the total number of hours have did for all students in each department.
query_toks: SELECT sum ( stu_hrs ) , dept_code FROM student GROUP BY dept_code
query_toks_no_value: select sum ( stu_hrs ) , dept_code from student group by dept_code
question_toks: Find the total number of hours have did for all students in each department.