Question

我想选择所有（WordPress）帖子以及最终brand和brand_id（均来自同一分类）。如果没有设置品牌，则应始终选择帖子，并将这两个字段设置为NULL。

此查询几乎可以正常运行，但不包括缺少品牌的帖子：

SELECT 
   p.ID AS post_id, 
   p.post_title AS title, 
   p.post_content AS body, 
   brand.name AS brand, 
   brand.term_id AS brand_id, 
   UNIX_TIMESTAMP(p.post_date) AS date_added 
FROM 
   wp_posts AS p 
INNER JOIN wp_term_relationships AS brand_rel
   ON brand_rel.object_id = p.ID 
INNER JOIN wp_term_taxonomy AS brand_tax
   ON brand_tax.term_taxonomy_id = brand_rel.term_taxonomy_id
   AND brand_tax.taxonomy = "product_brand" 
INNER JOIN wp_terms AS brand
   ON brand.term_id = brand_tax.term_id 
WHERE 
   p.post_type = 'product' AND 
   p.post_status = 'publish'
GROUP BY post_id;

从INNER JOIN更改为LEFT JOIN，我收到了所有帖子 - 但他们的品牌（brand和brand_id都不是NULL）：< / p>

SELECT 
   p.ID AS post_id, 
   p.post_title AS title, 
   p.post_content AS body, 
   brand.name AS brand, 
   brand.term_id AS brand_id, 
   UNIX_TIMESTAMP(p.post_date) AS date_added 
FROM 
   wp_posts AS p 
LEFT JOIN wp_term_relationships AS brand_rel
   ON brand_rel.object_id = p.ID 
LEFT JOIN wp_term_taxonomy AS brand_tax
   ON brand_tax.term_taxonomy_id = brand_rel.term_taxonomy_id
   AND brand_tax.taxonomy = "product_brand" 
LEFT JOIN wp_terms AS brand
   ON brand.term_id = brand_tax.term_id 
WHERE 
   p.post_type = 'product' AND 
   p.post_status = 'publish'
GROUP BY post_id;

但是，如果我在GROUP BY期间移除了LEFT JOIN声明，我似乎可以获得有和没有品牌的所有帖子，但也有很多重复的{{1} }}和brand字段为brand_id。

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选择帖子以及可选的分类

0 个答案: