使用两个表组合 SQL 查询

Question

是否可以将查询合并为一次调用？ UPDATE wp_term_taxonomy必须在第一个 UPDATE wp_posts 之后运行。

这是查询，我刚刚开始进行查询：

UPDATE  `wp_posts` p 
    LEFT OUTER JOIN wp_term_relationships r ON r.object_id = p.ID
    LEFT OUTER JOIN wp_term_taxonomy x ON x.term_taxonomy_id = r.term_taxonomy_id
    LEFT OUTER JOIN wp_terms t ON t.term_id = x.term_id
    SET  p.post_type =  'recipe'
    WHERE p.post_type = 'post'
    AND t.slug = 'recipes' 
    OR t.slug = 'cocktails' 
    OR t.slug = 'breakfast' 
    OR t.slug = 'cookies-recipes' 
    OR t.slug = 'desserts'
    OR t.slug = 'main-course'
    OR t.slug = 'sides'
    OR t.slug = 'soups'
    OR t.slug = 'starters'

UPDATE wp_term_taxonomy SET taxonomy = 'recipe-categories' WHERE term_taxonomy_id IN (53,57,72,75,125,138,177);

Answer 1

考虑使用CASE或IF表达式进行SET赋值。 下面还根据您似乎打算做的事情调整WHERE逻辑：

UPDATE `wp_posts` p 
LEFT OUTER JOIN wp_term_relationships r 
   ON r.object_id = p.ID 
LEFT OUTER JOIN wp_term_taxonomy x 
   ON x.term_taxonomy_id = r.term_taxonomy_id 
LEFT OUTER JOIN wp_terms t 
   ON t.term_id = x.term_id 
SET p.post_type = 'recipe',
    x.taxonomy = CASE 
                      WHEN x.term_taxonomy_id IN (53,57,72,75,125,138,177)
                      THEN 'recipe-categories'
                      ELSE x.taxonomy
                 END
WHERE p.post_type = 'post' 
  AND (   t.slug = 'recipes' 
       OR t.slug = 'cocktails' 
       OR t.slug = 'breakfast' 
       OR t.slug = 'cookies-recipes' 
       OR t.slug = 'desserts' 
       OR t.slug = 'main-course' 
       OR t.slug = 'sides' 
       OR t.slug = 'soups'
       OR t.slug = 'starters')