的MySQL排除查询

Question

我有一个wp_posts和wp_icl_translations表什么都跟对方wp_posts.ID和wp_icl_translations.trid。我想排除那些已经有翻译的帖子。 以下查询将检索我实际想要排除的所有这些行。

SELECT p.ID, 
     p.post_title 
FROM wp_posts AS p 
      JOIN wp_icl_translations AS t 
      ON p.ID= t.trid 
WHERE p.post_type = '{$type}' AND 
     p.post_status = 'publish' AND 
     t.language_code='en' AND 
     t.element_type='post_post' 
ORDER BY post_title; 

Answer 1

尝试（未测试）

使用NOT <>条件

SELECT p.ID,p.post_title 
FROM wp_posts AS p 
INNER JOIN wp_icl_translations AS t 
      ON p.ID= t.trid 
WHERE p.post_type = '{$type}' AND 
     p.post_status = 'publish' AND 
     t.language_code <>'en' AND 
     t.element_type='post_post' 
ORDER BY post_title; 

或

LEFT JOIN与IS NULL

SELECT p.ID,p.post_title 
FROM wp_posts AS p 
LEFT JOIN wp_icl_translations AS t 
      ON p.ID= t.trid 
WHERE p.post_type = '{$type}' AND 
     p.post_status = 'publish' AND 
     t.trid IS NULL 
ORDER BY post_title; 

Answer 2

ù se LEFT JOIN并选择IS NULL。

SELECT p.ID, 
     p.post_title 
FROM wp_posts AS p 
LEFT JOIN wp_icl_translations AS t ON p.ID= t.trid 
WHERE p.post_type = '{$type}' AND 
     p.post_status = 'publish' AND 
     t.trid IS NULL 
ORDER BY post_title; 

Answer 3

我会说这样的话;使用（NOT）IN运算符。但是可能有更好的解决方案（这种性能不应该那么好，也没有经过测试）。

SELECT ID, 
     post_title 
FROM wp_posts 
WHERE ID NOT IN 
(
     SELECT p.ID 
     FROM wp_posts AS p 
     JOIN wp_icl_translations AS t 
     ON p.ID= t.trid 
     WHERE p.post_type = '{$type}' AND 
      p.post_status = 'publish' AND 
      t.language_code='en' AND 
      t.element_type='post_post' 

) 
ORDER BY post_title;