Question

我有一个类似的表结构，因为这个问题接受了答案：Recommended SQL database design for tags or tagging

除了我的

thread, thread_tags and tags

使用以下SQL命令，我可以获得与每个线程关联的一个标记，如何获得与每个线程关联的所有标记？

SELECT 
  thread.id AS t_id, 
  thread.title, 
  thread.content, 
  author.username, 
  author.id AS a_id
FROM thread 
INNER JOIN author
  ON author_id = author.id
INNER JOIN thread_tags
  ON thread_id = thread.id
INNER JOIN tags
  ON tag_id = tags.id       
ORDER BY thread.created DESC

Answer 1

我认为您的联接看起来很好，但除非您将其放在那里，否则您不会从tags表中选择任何内容！ T.*以下

SELECT TH.id, TH.title, TH.content, A.username, A.id, T.*                  
FROM thread TH
INNER JOIN author A ON TH.author_id = A.id 
INNER JOIN thread_tags TT ON TT.thread_id = TH.id 
INNER JOIN tags T ON TT.tag_id = T.id 
ORDER BY TH.created DESC

在php中获取所有标签

1 个答案: