Question


    table wp_posts
    +-----+----------+
    | ID  |post_type |
    +-----+----------+
    |  1  |        A |
    |  2  |        A |
    |  3  |        A | 
    |  3  |        B | 
    |  3  |        C | 
    +-----+----------+


    table wp_term_relationships (object_id = wp_posts.ID)
    +-----------+------------------+
    | object_id | term_taxonomy_id |
    +-----------+------------------+
    |  1        |                1 |
    |  2        |                3 |
    |  2        |                2 |
    |  1        |                2 |
    |  3        |                1 | 
    +-----------+-------------------+


    table wp_esp_datetime (EVT_ID = wp_posts.ID)
    +-----------+---------------------+
    | EVT_ID    | DTT_EVT_end         |
    +-----------+---------------------+
    |  1        | 2015-12-01 16:00:00 |
    |  2        | 2015-12-01 16:00:00 |
    |  3        | 2015-12-01 16:00:00 |
    +-----------+---------------------+

现在我想做的是：使用wp_esp_datetime中的左连接日期时间查询来自wp_posts的所有内容，但仅查找在term_taxonomy_id = 3的wp_term_relationships中没有条目的人。我的问题是，在wp_term_relationships.object_id

中wp_post.ID可以多次

我当前的查询如下所示：

SELECT * FROM wp_posts 
INNER JOIN wp_term_relationships on wp_posts.ID = wp_term_relationships.object_id 
LEFT JOIN wp_esp_datetime on wp_posts.ID = wp_esp_datetime.EVT_ID
WHERE wp_posts.post_type = 'A' GROUP BY wp_posts.ID

所以问题是：

如何在wp_posts中排除wp_postss中包含term_taxonomy_id = 3的条目的行，即使与另一个term_taxonomy（不是3）匹配？

Answer 1

添加（not）exists子句

SELECT * FROM wp_posts p
INNER JOIN wp_term_relationships tr on p.ID = tr.object_id 
LEFT JOIN wp_esp_datetime ed on p.ID = ed.EVT_ID 
WHERE p.post_type = 'A' 
and not exists (select null 
                from wp_term_relationships
                where term_taxonomy_id = 3
                and p.ID = object_id)
GROUP BY p.ID

Answer 2

尝试添加子查询？

 AND wp_posts.ID NOT IN
(SELECT wtr2.object_id FROM wp_term_relationships wtr2 WHERE wtr2.term_taxonomy_id = 3)

您的查询已修改：

SELECT *
FROM wp_posts p
INNER JOIN wp_term_relationships wtr on p.ID = wtr.object_id
LEFT JOIN wp_esp_datetime wed on p.ID = wed.EVT_ID
WHERE p.post_type = 'A'
AND p.ID NOT IN (SELECT wtr2.object_id FROM wp_term_relationships wtr2 WHERE wtr2.term_taxonomy_id = 3)
GROUP BY p.ID

Answer 3

使用not exists并使用 wp_term_relationships 删除联接：

SELECT      p.ID, ed.DTT_EVT_end 
FROM        wp_posts p
LEFT JOIN   wp_esp_datetime ed on p.ID = ed.EVT_ID 
WHERE       p.post_type = 'A' 
AND         NOT EXISTS (
                SELECT  1 
                FROM    wp_term_relationships
                WHERE   term_taxonomy_id = 3
                AND     p.ID = object_id)
ORDER BY    p.ID, ed.DTT_EVT_end;

Answer 4

我无法看到以下问题无法解决的问题......

 +----+-----------+--------+---------------------+
 | ID | post_type | EVT_ID | DTT_EVT_end         |
 +----+-----------+--------+---------------------+
 |  1 | A         |      1 | 2015-12-01 16:00:00 |
 |  3 | A         |      3 | 2015-12-01 16:00:00 |
 |  3 | B         |      3 | 2015-12-01 16:00:00 |
 |  3 | C         |      3 | 2015-12-01 16:00:00 |
 +----+-----------+--------+---------------------+

这将产生以下结果......

{{1}}

将GROUP BY子句应用于此结果集似乎是荒谬的。

来自表A的Mysql行，其中ID来自查询，其中ID与表B中的一个条件为真

4 个答案: