MYSQL Заказывайте после GROUP BY не работает

Question

select manga_source_id, manga_episode_name, manga_episode_number 
from manga_chapter 

+-----------------+--------------------------------------+----------------------+ 
| manga_source_id | manga_episode_name     | manga_episode_number | 
+-----------------+--------------------------------------+----------------------+ 
|    5 | A Method to Make the World Gentle 1 |     1 | 
|    5 | A Method to Make the World Gentle 2 |     2 | 
|    5 | A Method to Make the World Gentle 3 |     3 | 
|    5 | A Method to Make the World Gentle 5 |     5 | 
|    5 | A Method to Make the World Gentle 6 |     6 | 
|    5 | A Method to Make the World Gentle 7 |     7 | 
|    5 | A Method to Make the World Gentle 8 |     8 | 
|    5 | A Method to Make the World Gentle 9 |     9 | 
|    5 | A Method to Make the World Gentle 10 |     10 | 
|    5 | A Method to Make the World Gentle 11 |     11 | 
|    5 | A Method to Make the World Gentle 12 |     12 | 
|    5 | A Method to Make the World Gentle 13 |     13 | 
|    5 | A Method to Make the World Gentle 14 |     14 | 
|    5 | A Method to Make the World Gentle 15 |     15 | 
|    5 | A Method to Make the World Gentle 16 |     16 | 
|    5 | A Method to Make the World Gentle 17 |     17 | 
|    5 | A Method to Make the World Gentle 18 |     18 | 
|    5 | A Method to Make the World Gentle 19 |     19 | 
|    5 | A Method to Make the World Gentle 20 |     20 | 
|    5 | A Method to Make the World Gentle 21 |     21 | 
|    5 | A Method to Make the World Gentle 22 |     22 | 
|    5 | A Method to Make the World Gentle 23 |     23 | 
|    5 | A Method to Make the World Gentle 24 |     24 | 
|    5 | A Method to Make the World Gentle 25 |     25 | 
|    5 | A Method to Make the World Gentle 26 |     26 | 
+-----------------+--------------------------------------+----------------------+ 
25 rows in set (0.00 sec) 

select manga_source_id, manga_episode_name, manga_episode_number 
from manga_chapter 
GROUP by manga_source_id 
ORDER BY manga_episode_number DESC 

+-----------------+-------------------------------------+----------------------+ 
| manga_source_id | manga_episode_name     | manga_episode_number | 
+-----------------+-------------------------------------+----------------------+ 
|    5 | A Method to Make the World Gentle 1 |     1 | 
+-----------------+-------------------------------------+----------------------+ 

Я пытался получить последний manga_episode_number, который Метод, чтобы сделать мир нежный 26 однако он не работает, я даже указать ORDER по manga_episode_number DESC

Как достичь чертежа последней записи, с GROUP от

спасибо!

Answer 1

Используйте подзапрос, чтобы получить максимальный эпизод, а затем присоединиться назад, чтобы получить остальную часть колонн:

select c.* 
from manga_chapter c join 
    (select manga_source_id, max(manga_episode_number) as maxmen 
     from manga_chapter 
     group by manga_source_id 
    ) cc 
    on c.manga_source_id = cc.manga_source_id and 
     c.manga_episode_number = cc.maxmen; 

Answer 2

Как нужно название манги на вашем запросе, и у вас есть еще идентификаторы это запрос вы хотите:

SELECT mc.manga_source_id, 
     mc.manga_episode_name, 
     mc.manga_episode_number 
    FROM manga_chapter mc INNER JOIN 
     (SELECT manga_source_id, max(manga_episode_number) mx 
      FROM manga_chapter 
      GROUP BY manga_source_id) mc_max 
         ON (mc.manga_source_id = mc_max.manga_source_id) 
          AND mc.manga_episode_number = mc_max.mx)