mysql - Mysql查询多个表检索所有结果甚至为null

Question

即使信息表中没有与所选语言相关的行，我也会尝试使此查询包含所有 products_options_name 结果。当我现在运行查询时，只显示 products_propoptions，它在信息表中具有与所选语言相关的行。

非常感谢任何帮助。在此先感谢，巴斯

SELECT PPO.products_options_name, I.information_title, PTL.information_id, 
COUNT(PPA.products_attributes_id) as amount, 
options_id FROM products_propattributes PPA 
INNER JOIN products_propoptions PPO ON PPA.options_id = PPO.products_options_id
LEFT JOIN properties_to_information PTL ON PPA.options_id = PTL.option_id   
LEFT JOIN information I ON PTL.information_id = I.information_id
WHERE PPO.language_id = 6 AND I.language_id = 6 AND PPA.products_id = 121
GROUP BY PPA.options_id ORDER BY PPA.products_options_sort_order

表：products_propoptions

• products_options_id
• 语言标识
• products_options_name
• products_options_sort_order

表：products_propattributes

• products_attributes_id
• products_id
• options_id
• options_values_id
• options_values_price
• 价格前缀
• products_options_sort_order

表：信息

• 信息ID
• information_group_id
• 信息标题
• 信息描述
• parent_id
• 排序
• 可见的
• 无索引
• 语言标识

表：properties_to_information

• properties_to_information_id
• option_id
• 信息ID

Answer 1

这修复了它.. 包括 LEFT OUTER JOINS 以及连接中的 where 条件......谢谢.. Bas

SELECT 
PPO.products_options_name,
PTL.lexicon_id, 
I.information_title, 
COUNT(PPA.products_attributes_id) as amount, 
options_id 
FROM products_propattributes PPA  
LEFT OUTER JOIN products_propoptions PPO ON PPA.options_id = PPO.products_options_id AND PPO.language_id = 6
LEFT OUTER JOIN  properties_to_information PTL ON PPA.options_id = PTL.option_id   
LEFT OUTER JOIN information I ON PTL.lexicon_id = I.information_id  AND I.language_id = 6
WHERE PPA.products_id = 121
GROUP BY PPA.options_id ORDER BY PPA.products_options_sort_order

Answer 2

您是否尝试过将 INNER JOIN 更改为 LEFT JOIN？INNER JOIN 可能会导致查询省略您正在寻找的结果集行。