Question

我有表'文章'

+-------------+
|   articles  |
+----+--------+
| id | title  |
+----+--------+
| 1  | title1 |
+----+--------+
| 2  | title2 |
+----+--------+
| 3  | title3 |
+----+--------+

表'目录'

+---------------------+
|      catalogue      |
+----+--------+-------+
| id | group  | name  |
+----+--------+-------+
| 1  | group1 | name1 |
+----+--------+-------+
| 2  | group1 | name2 |
+----+--------+-------+
| 3  | group2 | name3 |
+----+--------+-------+
| 4  | group2 | name4 |
+----+--------+-------+

绑定表'bindTable'

+------------+--------------+-------+
|              bindTable            |
+------------+--------------+-------+
| id_article | id_catalogue | value |
+------------+--------------+-------+
|     1      |      2       |   1   |
+------------+--------------+-------+
|     1      |      3       |   4   |
+------------+--------------+-------+
|     3      |      1       |   2   |
+------------+--------------+-------+
|     3      |      3       |   1   |
+------------+--------------+-------+
|     3      |      4       |   3   |
+------------+--------------+-------+

我需要获得结果，如表'结果'，我可以从表'article'获得所选项目的“catalogue_name：value”对

+-----------------------------------------------------+
|                        result                       |
+------------+---------------+----------------+-------+
| article_id | article_title | catalogue_name | value |
+------------+---------------+----------------+-------+
|      1     |     title1    |  group1_name2, |   1   |
|            |               |  group2_name3  |   4   |
+------------+---------------+----------------+-------+
|      3     |     title3    |  group1_name1, |   2   |
|            |               |  group2_name3, |   1   |
|            |               |  group2_name4  |   3   |
+------------+---------------+----------------+-------+

有人能用一个数据库查询告诉我一个查询字符串吗？谢谢你的关注。

My vision: 
    SELECT b.id_article, a.title, c.group, c.name, b.value 
    FROM bindTable b
    JOIN articles a ON a.id = b.id_articles
    JOIN catalogue c ON c.id = b.id_catalogue
    WHERE b.id_article = 1

但是对于一个a.id

，我需要一对c.name＆amp; b.value对

Answer 1

具有内部联接的选择

select a.article_id, a.article_title, b.catalogue_name, b.value
from bindTable as c
inner join articles as a on a.id = c. article_id
inner join catalogues as b on c. id_catalogue = b.id

Answer 2

这应该这样做。

SELECT articles.id AS article_id, 
       articles.title AS article_title, 
       CONCAT_WS('_', catalogue.group, catalogue.name) AS catalogue_name,
       bindTable.value AS value
FROM bindTable
  INNER JOIN articles ON bindTable.id_article = articles.id
  INNER JOIN catalogue ON bindTable.id_catalogue = catalogue.id

如何从两个表中进行选择？

2 个答案: