How many classes exist for each school?
SELECT count(*) ,  T3.school_code FROM CLASS AS T1 JOIN course AS T2 ON T1.crs_code  =  T2.crs_code JOIN department AS T3 ON T2.dept_code  =  T3.dept_code GROUP BY T3.school_code
SELECT count(*) ,  T3.school_code FROM CLASS AS T1 JOIN course AS T2 ON T1.crs_code  =  T2.crs_code JOIN department AS T3 ON T2.dept_code  =  T3.dept_code GROUP BY T3.school_code
[{'count(*)': 13, 'SCHOOL_CODE': 'BUS'}]