MySQL查詢條件

Question

我有以下MySQL查詢（查詢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 

我基本上是試圖阻止所有「wp_posts」回來有一個標籤（db表wp_terms）' MyTagName」。但是，以上所有內容似乎都是從返回的行中去除該標記名稱，並將wp_post條目與其標記的其他標記條目相關聯。

任何人都可以幫助我嗎？

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 

問題是，您當前的解決方案沒有檢查與帖子相關的所有wp_terms，只是特定的一個。如果有5個條款，其中之一是'MyTagName'，那麼單個條款將被排除，但其他4個條款仍將被加入。

現在有關：

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

你並不需要把他們在大NOT EXISTS檢查，因爲該職位將不會被無論如何拿起其中任何一項都是假的。