Question

这是我的表结构：

// posts
+----+-----------------------------+-----------+------------+
| id |            body             | edited_id | date_time  |
+----+-----------------------------+-----------+------------+
| 1  | post1                       | NULL      | 1464136759 |
| 2  | post2                       | NULL      | 1464136760 | 
| 3  | post2     edited            | 2         | 1464136761 | 
| 4  | post2     eduted again      | 2         | 1464136762 | 
+----+-----------------------------+-----------+------------+

如您所见，上表保留了帖子及其版本。目前我正在选择这样的帖子：

SELECT * FROM posts WHERE id IN (1,2) ORDER BY date_time ASC;

当前输出：

| 1  | a question                  | NULL      | 1464136759 |
| 2  | my answer                   | NULL      | 1464136760 |

预期输出：

| 1  | a question                  | NULL      | 1464136759 |
| 4  | my answer eduted again      | 2         | 1464136762 |

见？帖子id = 2有两个版本，我总是需要选择最大版本（根据date_time）。我怎么能这样做？

Answer 1

如果未对行进行编辑，则可以使用：

select p.*
from posts p
where (p.id in (1, 2) or p.edited_id in (1, 2)) and
      p.id = (select p2.id
              from posts p2
              where p.id in (p2.id, p2.edited_id)
              order by date_time desc
              limit 1
             );

如何在MySQL中选择最后编辑的帖子版本？

1 个答案: