MYSQL IN语句在select查询中返回重复项

我有一个select查询，它应该返回连接到多个团队ID的新闻。为此，我使用IN语句和所选的团队ID。例如，在本例中，我选择了id为1和2的团队，如您所见

问题是，两个团队可能会联系到同一条新闻，因此我不想重复同一条新闻？我如何确保即使团队可能连接到同一条新闻，也没有重复的新闻

 SELECT news.id,
   news.title,
   news.url,
   news.image_url,
   news.date,
   news.news_text,
   website.url   AS website_url,
   website.image AS website_image
FROM   news,
       team,
       contain,
       website
WHERE  team.id IN ( 1, 2 )
       AND news.website_id = website.id
       AND team.id = contain.team_id
       AND contain.news_id = news.id
ORDER  BY news.date DESC
LIMIT  0, 30  

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使用带有适当连接条件的显式连接

SELECT 
n.id, 
n.title, 
n.url, 
n.image_url, 
n.date, 
n.news_text, 
w.url as website_url, 
w.image as website_image 
from news n
join contain c on c.news_id = n.id
join team t on t.id = c.team_id
join website w on w.id = n.website_id
where  t.id in (1,2)
ORDER BY n.date DESC LIMIT 0, 30

请注意，在执行join时，如果在其他表中多次预设了项目，即

1,2

，则它将出现多次。如果您想摆脱这种情况，请使用

groupby

where  t.id in (1,2)
group by t.id

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但是这将从关联ID的联接表中选择随机数据

1,2

那么

DISTINCT

呢？ 为避免重复结果，请执行以下操作：

    SELECT DISTINCT news.id, news.title, news.url, news.image_url, 
news.date, news.news_text, website.url as website_url, 
website.image as website_image from news, team, contain, website 
WHERE team.id in (1,2)
 AND news.website_id = website.id
 AND team.id = contain.team_id
 AND contain.news_id = news.id 
 ORDER BY news.date DESC LIMIT 0, 30

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这是因为它是笛卡尔积