For students who have pets , how many pets does each student have ? list their ids instead of names .
select count(*) ,  t1.stuid from student as t1 join has_pet as t2 on t1.stuid  =  t2.stuid group by t1.stuid
select count(*) ,  t1.stuid from student as t1 join has_pet as t2 on t1.stuid  =  t2.stuid group by t1.stuid
[{'count(*)': 1, 'StuID': 1001}, {'count(*)': 2, 'StuID': 1002}]