php - 如何使以下 $query 工作在 Enrollments.Quiz_id 上使用 DISTINCT 以摆脱双三重记录

Question

SELECT SUM(ticketfee * enrolledplayers)
FROM Quiz
 INNER JOIN Enrollment on DISTINCT(Quiz.id) AND Quiz.id=Enrollment.Quiz_id
WHERE (Quiz.state=3 OR Quiz.state=4) AND Enrollment.promocoupon_id IS NULL

Answer 1

SELECT DISTINCT(Quiz.id), SUM(ticketfee * enrolledplayers)
FROM Quiz
JOIN Enrollment on Quiz.id = Enrollment.Quiz_id
WHERE (Quiz.state=3 OR Quiz.state=4) AND Enrollment.promocoupon_id IS NULL