Question

我有一个内容表，可以有与每行关联的注释和标记的不同结果长度。我不确定如何一举得到所有这些信息。

我可以轻松地进行查询以获取内容信息（id）并查询每个表中的注释和标签，但这似乎并不像是有更好的方法。

任何提示或建议？提前谢谢！

托马斯

我的查询远远看起来像：

SELECT c.*, GROUP_CONCAT(tagWords.tagWord SEPARATOR ', ') AS tags FROM platform.contents c
LEFT OUTER JOIN platform.contentTags ON contentTags.contentId = c.contentId
LEFT OUTER JOIN platform.tagWords ON contentTags.tagId = tagWords.tagId
WHERE  c.contentType = 'album' LIMIT 10

GROUP_CONCAT很棒，除了我需要每个表中的字段，因为表格会增长。：/

我的表格布局：

mysql> explain contentComments;
+--------------+---------------------+------+-----+-------------------+-------+
| Field        | Type                | Null | Key | Default           | Extra |
+--------------+---------------------+------+-----+-------------------+-------+
| contentId    | bigint(19) unsigned | NO   | MUL | NULL              |       |
| userId       | bigint(19) unsigned | NO   |     | NULL              |       |
| message      | varchar(255)        | YES  |     | NULL              |       |
| stampCreated | timestamp           | NO   |     | CURRENT_TIMESTAMP |       |
+--------------+---------------------+------+-----+-------------------+-------+
4 rows in set (0.00 sec)

mysql> explain contentTags;
+-----------+------------+------+-----+---------+-------+
| Field     | Type       | Null | Key | Default | Extra |
+-----------+------------+------+-----+---------+-------+
| contentId | bigint(20) | NO   | MUL | NULL    |       |
| tagId     | bigint(20) | YES  |     | NULL    |       |
+-----------+------------+------+-----+---------+-------+
   2 rows in set (0.00 sec)

mysql> explain contents;
+------------------+-----------------------------------------+------+-----+-------------------+----------------+
| Field            | Type                                    | Null | Key | Default                   | Extra          |
+------------------+-----------------------------------------+------+-----+-------------------+----------------+
| contentId        | bigint(20)                              | NO   | PRI | NULL              | auto_increment |
| contentType      | enum('video','album','blogpost','news') | NO   |     | NULL              |                |
| userId           | bigint(19) unsigned                     | NO   | MUL | NULL              |                |
| contentTitle     | varchar(45)                             | YES  |     | NULL              |                |
| contentDesc      | varchar(255)                            | YES  |     | NULL                  |                |
+------------------+-----------------------------------------+------+-----+-------------------+----------------+

mysql> explain tagWords;
+---------+---------------------+------+-----+---------+----------------+
| Field   | Type                | Null | Key | Default | Extra          |
+---------+---------------------+------+-----+---------+----------------+
| tagId   | bigint(19) unsigned | NO   | PRI | NULL    | auto_increment |
| tagWord | varchar(45)         | YES  |     | NULL    |                |
+---------+---------------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)

Answer 1

看起来对我来说，虽然我认为你还需要一个group_concat来评论。可能是你的大脑对数据库中N到N关系的想法感到不舒服，考虑到它看起来像你做得对，这会很奇怪：p

使用不同长度的注释和标签加入内容项：D

1 个答案: