mysql DISTINCT 关键字不显示不同的行

Question

查询:

mysql> SELECT DISTINCT (stories.id), stories.news_type, story_keywords.keyword 
FROM (`stories`) LEFT JOIN `story_keywords` ON `stories`.`id`
=`story_keywords`.`story_id` 
WHERE `image_full_url` != '' AND `order` != 0 
AND `news_type` IN ('movie_review', 'movie') 
AND `keyword` IN ('topnews', 'toptablet') 
ORDER BY `created` DESC, `order` DESC LIMIT 5;

结果:(注意 ID 不是不同的)

+--------+--------------+-----------+
| id     | news_type    | keyword   |
+--------+--------------+-----------+
| 100895 | movie_review | topnews   |
| 100895 | movie_review | toptablet |
| 100798 | movie_review | toptablet |
| 100060 | movie_review | toptablet |
| 100060 | movie_review | topnews   |
+--------+--------------+-----------+
5 rows in set (0.00 sec)

Answer 1

select distinct 适用于正在获取的行，而不是该行中的各个字段。结果集中的每一行都是不同的。