Question

因此,我需要从一个表格中选择不同的价值观,但从另一个表格中加入所有相关的价值观,但在同一询问中加入。

http://forge.mysql.com/wiki/TagSchema#Toxi”rel=“nofollow”http://forge.mysql.com/wiki/TagSchema#Toxi。

3. 绘制三表的多层次地图。

而且,我需要在各个行中显示所有插入的数值(docs),但我想一栏中有一个一栏是,档案中的所有标记都用 com子分开。

现在我

SELECT 
    docs.id AS id, 
    docs.orig_file AS orig_file, 
    docs.date_sent AS date_sent, 
    tags.tag_name AS alltags
FROM documat AS docs
LEFT JOIN documat_file2tag AS f2t ON f2t.doc_id = docs.id
LEFT JOIN documat_tags AS tags ON tags.id = f2t.tag_id

但是,如果是具体的话,这又是重复一行。补贴不止是tag。我每行的最后结果是:

| ID | orig_file | date_sent | alltags |

预期成果:

| X | example_value.pdf | 2012-03-23 10:14:05 | tag_ex_1, tag_ex_2, etc |

Answer 1

Concat:

SELECT 
    docs.id AS id, 
    docs.orig_file AS orig_file, 
    docs.date_sent AS date_sent, 
    GROUP_CONCAT(distinct tags.tag_name) AS alltags
FROM documat AS docs
LEFT JOIN documat_file2tag AS f2t ON f2t.doc_id = docs.id
LEFT JOIN documat_tags AS tags ON tags.id = f2t.tag_id
GROUP BY docs.id

友情链接