SELECT e.name, b.bonus

FROM Employee e

LEFT JOIN Bonus b ON e.empId = b.empId

WHERE b.bonus < 1000 OR b.bonus IS NULL;

SELECT s.student_id, s.student_name, sub.subject_name, COUNT(e.student_id) AS attended_exams

FROM Students AS s

INNER JOIN Subjects AS sub

LEFT JOIN Examinations as e

ON (s.student_id = e.student_id AND sub.subject_name = e.subject_name)

GROUP BY s.student_id, sub.subject_name

ORDER BY student_id, subject_name

SELECT name

FROM Employee

WHERE id

IN

(

SELECT managerId

FROM Employee

GROUP BY managerId

HAVING count(*)>=5

)

s.user_id,

IFNULL(ROUND(SUM(CASE WHEN c.action = 'confirmed' THEN 1 ELSE 0 END) / COUNT(c.user_id), 2), 0) AS confirmation_rate

Signups s

LEFT JOIN Confirmations c ON s.user_id = c.user_id

s.user_id;