MySQL-连接表，仅检索最大ID

Question

我在其他帖子上也看到了类似问题的解决方案，但是在将其应用于我的特定问题时遇到了问题。

这是我最初的加入：

SELECT service_note_task, comment_id, comment FROM service_note_task LEFT JOIN service_note_task_comments ON service_note_task.service_note_task_id = service_note_task_comments.service_note_task_id;

结果是：

+-----------------------------+------------+--------------+
| service_note_task           | comment_id | comment      |
+-----------------------------+------------+--------------+
| This is service note task 3 |         25 | Comment      |
| This is service note task 3 |         26 | Comment Blah |
| This is service note task 3 |         36 | aaa          |
| This is service note task 2 |         13 | Awesome comm |
| This is service note task 1 |         12 | Cool Comm    |
+-----------------------------+------------+--------------+

但是对于每个service_note_task，我实际上只需要一行代表具有最高comment_id的注释，如下所示：

+-----------------------------+------------+--------------+
| service_note_task           | comment_id | comment      |
+-----------------------------+------------+--------------+
| This is service note task 3 |         36 | aaa          |
| This is service note task 2 |         13 | Awesome comm |
| This is service note task 1 |         12 | Cool Comm    |
+-----------------------------+------------+--------------+

我认为我可以在子选择语句中使用MAX来缩小结果的范围。如何将其合并到语句中以获得这些结果？

Answer 1

作为参考，这被称为“ groupwise-maximum”

http://dev.mysql.com/doc/refman/5.0/en/example-maximum-column-group-
row.html