Find the number of pets for each student who has any pet and student id.
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}]