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  • 596. Classes More Than 5 Students

    There is a table courses with columns: student and class

    Please list out all classes which have more than or equal to 5 students.

    For example, the table:

    +---------+------------+
    | student | class      |
    +---------+------------+
    | A       | Math       |
    | B       | English    |
    | C       | Math       |
    | D       | Biology    |
    | E       | Math       |
    | F       | Computer   |
    | G       | Math       |
    | H       | Math       |
    | I       | Math       |
    +---------+------------+
    

    Should output:

    +---------+
    | class   |
    +---------+
    | Math    |
    +---------+
    

     

    Note:
    The students should not be counted duplicate in each course.

    请列出所有超过或等于5名学生的课程。

    可能会有重复行

    MySQL(2707ms):

    # Write your MySQL query statement below
    SELECT class
    FROM courses
    GROUP BY class
    HAVING COUNT(DISTINCT student) >= 5 ;
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  • 原文地址:https://www.cnblogs.com/mengchunchen/p/8317903.html
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