MySQL 子查询错误 : SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'id'

Question

我正在努力让以下 MySQL 语句正常工作。

SELECT ItemGroup.users_id,ItemGroup.comments_id,ItemGroup.uploads_id,ItemGroup.posts_id, 
                Comment.id,Comment.uploads_id,
                CommentUpload.id,
                Upload.id,
                Post.id
                FROM items AS ItemGroup
                LEFT JOIN (
                    SELECT Comment.id, Comment.uploads_id, CommentUpload.id, CommentUpload.uuid
                    FROM comments As Comment
                    INNER JOIN (
                        SELECT CommentUpload.id, CommentUpload.uuid
                        FROM uploads AS CommentUpload
                        ) CommentUpload ON CommentUpload.id = Comment.uploads_id
                    GROUP BY Comment.uploads_id
                ) Comment ON Comment.id = ItemGroup.comments_id
                LEFT JOIN (
                    SELECT Upload.id
                    FROM uploads AS Upload
                    ) Upload ON Upload.id = ItemGroup.uploads_id
                LEFT JOIN (
                    SELECT Post.id
                    FROM posts AS Post
                    ) Post ON Post.id = ItemGroup.posts_id
                WHERE ItemGroup.users_id = {$__cakeID__$}
                AND (
                Comment.id IS NOT NULL 
                OR Upload.id IS NOT NULL 
                OR Post.id IS NOT NULL
                )
                LIMIT 0 , 300

我试图找到与评论相关的上传，但它抛出 SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'id'。

我确定这是小事，但我就是找不到我做错了什么，我真的很感激能得到一些帮助。

感谢您的宝贵时间!

亚历克斯

Answer 1

你不能用相同的别名命名两个表 FROM comments As Comment 和 GROUP BY Comment.uploads_id) Comment，使用 Comment_A 和 Comment_B 例如。