Question

我有这个SQL行：

$sql = "SELECT id, title, url, description, champion, video_length, datemade FROM our_videos UNION SELECT id, title, url, description, champion, video_length, datemade FROM combo_videos ORDER BY datemade DESC LIMIT 10";

为了进一步开展工作，我需要知道在查询中使用了哪个表，是our_vidoes还是combo_videos，两个表看起来都一样但是数据中有不同的数据，所以我该怎么做检查一下？

Answer 1

使用Mysql，您可以执行以下操作：

选择“something”作为columnName;

您可以像这样修改您的查询：

$sql = "SELECT id, title, url, description, champion, video_length, datemade, "our_videos" as tableName FROM our_videos UNION SELECT id, title, url, description, champion, video_length, datemade, "our_videos" as tableName FROM combo_videos ORDER BY datemade DESC LIMIT 10";

对于返回的每一行，您可以检查“tableName”参数，以了解它的来源。

任何原因，为什么你有两个看起来相似的表，你可能想要考虑合并它们并添加一列来区分“combo_videos”或“our_videos”。

Answer 2

使用union all并将表添加到每个子查询中：

SELECT 'our_videos' as which, id, title, url, description, champion, video_length, datemade
FROM our_videos
UNION ALL
SELECT 'combo_videos' as which, id, title, url, description, champion, video_length, datemade
FROM combo_videos
ORDER BY datemade DESC
LIMIT 10;

PHP，MySql：如何知道使用了哪个表

2 个答案: