Database: cre_Students_Information_Systems
Question: List the biographical data and student id for the students who take 2 or more classes and the students who have less than 2 detentions.
SQL:
SELECT T1.bio_data ,  T1.student_id FROM Students AS T1 JOIN Classes AS T2 ON T1.student_id  =  T2.student_id GROUP BY T1.student_id HAVING count(*)  >=  2 UNION SELECT T1.bio_data ,  T1.student_id FROM Students AS T1 JOIN Detention AS T2 ON T1.student_id  =  T2.student_id GROUP BY T1.student_id HAVING count(*)  <  2