Php 根据字段的值从不同的表中获取值

在我的项目中，我有两种类型的视频：免费视频和特色视频。我正在将免费视频的详细信息保存在一个表channel_videos中，如下所示：

id  videotitle    video     thumbnail  added_on

我正在将特色视频的详细信息保存在表格视频中

当用户观看视频时，观看的视频详细信息以及观看的用户详细信息将存储在另一个表viewedmovies中

在此表中，如果字段videotype的值为0（免费视频），则查询表channel_videos，如果videotype为1（特色视频），则查询表videos

以上是我使用的查询。但这只从视频表中获取结果

如何在单个查询中完成此操作？此外，我希望将结果分组到viewedmovies表的movie_id、videotype和user_id字段中

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提前感谢。

我还没有测试过它，但类似的东西应该可以工作：

SELECT viewedmovies.id, viewedmovies.watched_on
, video.title, video.videothumbnail, video.views, video.likes, video.length, video.videoid
, channel_videos.videotitle, channel_videos.thumbnail, channel_videos.id
 FROM viewedmovies
 LEFT JOIN video
 ON (viewedmovies.movie_id=video.videoid AND viewedmovies.user_id=1 AND viewedmovies.videotype=1)
 LEFT JOIN channel_videos
 ON (viewedmovies.movie_id=channel_videos.id AND viewedmovies.user_id=1 AND viewedmovies.videotype=0)
 GROUP BY viewedmovies.user_id, viewedmovies.movie_id, viewedmovies.videotype
 ORDER BY watched_on desc
 LIMIT 6

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虽然总是有一些SQL魔力可以满足您的需求，但我认为您的数据库结构存在问题。由于免费视频和特色视频的信息是相同的，如果你把它们放在同一张表中，事情会变得容易得多。你只需要添加一个“is_free”列。

id   user_id   movie_id   videotype    watched_on

select viewedmovies.id,viewedmovies.watched_on,video.title,video.videothumbnail,video.views,
video.likes,video.length,video.videoid from viewedmovies INNER JOIN video ON viewedmovies.movie_id=video.videoid
and viewedmovies.user_id=1 group by viewedmovies.user_id,viewedmovies.movie_id,viewedmovies.videotype order by watched_on desc LIMIT 6

SELECT viewedmovies.id, viewedmovies.watched_on
, video.title, video.videothumbnail, video.views, video.likes, video.length, video.videoid
, channel_videos.videotitle, channel_videos.thumbnail, channel_videos.id
 FROM viewedmovies
 LEFT JOIN video
 ON (viewedmovies.movie_id=video.videoid AND viewedmovies.user_id=1 AND viewedmovies.videotype=1)
 LEFT JOIN channel_videos
 ON (viewedmovies.movie_id=channel_videos.id AND viewedmovies.user_id=1 AND viewedmovies.videotype=0)
 GROUP BY viewedmovies.user_id, viewedmovies.movie_id, viewedmovies.videotype
 ORDER BY watched_on desc
 LIMIT 6