获取php中的所有标签

Question

我有一个与此问题相似的表结构接受答案：Recommended SQL database design for tags or tagging

我的除外

thread, thread_tags and tags

使用下面的SQL命令我可以得到每个线程关联的一个标签，我怎样才能得到每个线程关联的所有标签？

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不错，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.*下方

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