力扣——超过5名学生的课(数据库的题
有一个courses
表 ,有: student (学生) 和 class (课程)。
请列出所有超过或等于5名学生的课。
例如,表:
+---------+------------+ | student | class | +---------+------------+ | A | Math | | B | English | | C | Math | | D | Biology | | E | Math | | F | Computer | | G | Math | | H | Math | | I | Math | +---------+------------+
应该输出:
+---------+ | class | +---------+ | Math | +---------+
Note:
学生在每个课中不应被重复计算。
# Write your MySQL query statement below select class from( select class from courses group by class,student )a group by class having count(class) >= 5