duanqian8867 2017-12-12 09:22
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MySQL Group by,Order by Two Columns

I want to get the last episode name of each movie

Table structure:

+---------+------------+---------------+
|     id  |  movie_id  |  episode_name |
+---------+------------+---------------+
|      1  |         1  |             1 |
|      2  |         1  |             2 |
|      3  |         1  |             3 |
|      4  |         2  |             1 |
|      5  |         3  |             1 |
|      6  |         2  |             2 |
|      7  |         1  |             4 |
|      8  |         2  |             3 |
|      9  |         4  |             1 |
+---------+------------+---------------+

Query 1:

SELECT * FROM episode
group by movie_id
order by id desc, episode_name desc LIMIT 10

Query 2:

SELECT * FROM episode
WHERE movie_id IN (select movie_id from episode group by movie_id)
group by movie_id
order by episode_name desc

But the output doesn't what i want, maybe i do it wrong way

+--------+------------+---------------+
|  id    |  movie_id  |  episode_name |
+--------+------------+---------------+
|     9  |         4  |             1 |
|     5  |         3  |             1 |
|     4  |         2  |             1 |
|     1  |         1  |             1 |
+--------+------------+---------------+

My desired result is:

+---------+------------+---------------+
|     id  |  movie_id  |  episode_name |
+---------+------------+---------------+
|      9  |         4  |             1 |
|      8  |         2  |             3 |
|      7  |         1  |             4 |
|      5  |         3  |             1 |
+---------+------------+---------------+
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2条回答 默认 最新

  • duangu8264 2017-12-12 09:29
    关注

    This is a pretty common problem, which we can handle in MySQL by joining the episode table to a subquery which finds the latest episode for each movie. This approach gives us the full matching latest records, including the id column, which we can then use to order the result set.

    SELECT e1.*
    FROM episode e1
    INNER JOIN
    (
        SELECT movie_id, MAX(episode_name) AS max_episode_name
        FROM episode
        GROUP BY movie_id
    ) e2
        ON e1.movie_id = e2.movie_id AND
           e1.episode_name = e2.max_episode_name
    ORDER BY
        e1.id DESC;
    

    Demo

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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