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Php mysql多字段连接查询_Php_Mysql - Fatal编程技术网

Php mysql多字段连接查询

Php mysql多字段连接查询,php,mysql,Php,Mysql,我在mysql中有以下表格 焦点 焦点事件 id event_id focus_id 1 1 2 2 1 1 3 2 1 事件 event_id name 1 event 2 evemt2 故事 事件与故事 id event_id story_id 2 2 这是我的问题 SELECT `focus`.`focus_id`, `focus`.`focus`, `e

我在mysql中有以下表格

焦点

焦点事件

id  event_id    focus_id
1   1           2
2   1           1
3   2           1
事件

event_id name 
1        event
2        evemt2
故事

事件与故事

id event_id story_id
2           2
这是我的问题

SELECT `focus`.`focus_id`, `focus`.`focus`, `events`.`event_id`, `events`.`name`, `story`.`story_id`, `story`.`name` 
FROM (`focus`) 
JOIN `events_focus` ON `events_focus`.`focus_id` = `focus`.`focus_id` 
JOIN `events` ON `events`.`event_id` = `events_focus`.`event_id` 
JOIN `events_story` ON `events_story`.`event_id` = `events`.`event_id` 
JOIN `story` ON `story`.`story_id` = `events_story`.`story_id` 
WHERE `focus`.`focus` = 'Company'
但我得到的结果是零


有谁能帮助我如何获取与我显示的表相关的所有数据。

event\u id
events\u story
所以下面的连接不起作用

JOIN `events_story` ON `events_story`.`event_id` = `events`.`event_id` 

如果此数据是预期的/有效的,您可能希望将联接从
join
更改为
LEFT-OUTER-join
使用
LEFT-join
而不是
join
。您将发现哪个表返回
NULL
值,即使用just
JOIN

时将引发0结果您的事件故事表值看起来不正确。事件id为空或故事id为空?我假设id为PK,因此值为2,这可能是结果为空的原因?
SELECT `focus`.`focus_id`, `focus`.`focus`, `events`.`event_id`, `events`.`name`, `story`.`story_id`, `story`.`name` 
FROM (`focus`) 
JOIN `events_focus` ON `events_focus`.`focus_id` = `focus`.`focus_id` 
JOIN `events` ON `events`.`event_id` = `events_focus`.`event_id` 
JOIN `events_story` ON `events_story`.`event_id` = `events`.`event_id` 
JOIN `story` ON `story`.`story_id` = `events_story`.`story_id` 
WHERE `focus`.`focus` = 'Company'
JOIN `events_story` ON `events_story`.`event_id` = `events`.`event_id`