MySQL查询条件

Question

我有以下MySQL查询（查询WordPress的DB）：

SELECT wp_posts.ID, wp_posts.post_date, wp_posts.post_content, wp_posts.post_title, wp_terms.name, wp_term_taxonomy.taxonomy 
FROM wp_posts 
LEFT JOIN wp_term_relationships ON (wp_term_relationships.object_id = wp_posts.ID) 
LEFT JOIN wp_term_taxonomy ON (wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id) 
LEFT JOIN wp_terms ON (wp_terms.term_id = wp_term_taxonomy.term_id) 
WHERE 1=1 
AND wp_terms.name != 'MyTagName' 
AND wp_posts.post_type = 'post' 
AND (wp_posts.post_status = 'publish') 
ORDER BY wp_posts.post_date DESC 
LIMIT 100 

我基本上是试图阻止所有“wp_posts”回来有一个标签（db表wp_terms）' MyTagName”。但是，以上所有内容似乎都是从返回的行中去除该标记名称，并将wp_post条目与其标记的其他标记条目相关联。

任何人都可以帮助我吗？

Answer 1

SELECT wp_posts.ID, wp_posts.post_date, wp_posts.post_content, wp_posts.post_title, wp_terms.name, wp_term_taxonomy.taxonomy 
FROM wp_posts 
JOIN wp_term_relationships ON wp_term_relationships.object_id = wp_posts.ID 
JOIN wp_term_taxonomy ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id 
JOIN wp_terms ON wp_terms.term_id = wp_term_taxonomy.term_id 
WHERE NOT EXISTS (
    SELECT 1 
    FROM wp_term_relationships 
    JOIN wp_term_taxonomy ON wp_term_taxonomy.term_taxonomy_id = wp_term_relationships.term_taxonomy_id 
    JOIN wp_terms ON wp_terms.term_id = wp_term_taxonomy.term_id 
    WHERE wp_term_relationships.object_id = wp_posts.ID 
     AND wp_terms.name = 'MyTagName' 
    ) 
    AND wp_posts.post_type = 'post' 
    AND wp_posts.post_status = 'publish' 
ORDER BY wp_posts.post_date DESC 
LIMIT 100 

问题是，您当前的解决方案没有检查与帖子相关的所有wp_terms，只是特定的一个。如果有5个条款，其中之一是'MyTagName'，那么单个条款将被排除，但其他4个条款仍将被加入。

现在有关：

AND wp_posts.post_type = 'post' 
AND wp_posts.post_status = 'publish' 

你并不需要把他们在大NOT EXISTS检查，因为该职位将不会被无论如何拿起其中任何一项都是假的。