Question

我在数据库中有一个名为“articles”的表

文章：

id +++   writer_id    +++     title     ++++    text
----------------------------------------------------
1           1              some title        article for writer 1 
2           1              some title        article for writer 1 
3           2              some title        article for writer 2 
4           2              some title        article for writer 2 
5           2              some title        article for writer 2
6           3              some title        article for writer 3

我需要一个查询来获取表格中的最新文章，但每个作家只需要一篇文章

取决于查询上面的行应该只获得3行：每篇文章由一位作家拥有

2           1              some title        article for writer 1 
5           2              some title        article for writer 2
6           3              some title        article for writer 3

PHP

SELECT * 
FROM articles
WHERE writer_id = ???? ;
order by id desc limit 10

提前感谢：）

Answer 1

使用GROUP BY和HAVING的组合，您可以获得每位作者撰写的最后一篇文章，并让他们正确订购：

SELECT * 
FROM articles
WHERE writer_id = ????
GROUP BY writer_id
HAVING id = MAX(id)
ORDER BY id DESC
LIMIT 10

Answer 2

短而甜蜜：

SELECT MAX(id), writer_id, title, text FROM articles GROUP BY writer_id;

Answer 3

使用子查询获取每个作者的最新文章ID ：

SELECT * FROM articles
WHERE id in
(
    SELECT MAX(id) id, writer_id
    FROM articles
    GROUP BY writer_id
)

Mysql查询GROUP BY条件LIMIT 1

3 个答案: