MySQL 查询通过数据透视表返回最常用的标签

Question

我有 3 个表:

threads (thread_id and thread_title)
tags (tag_id and tag_name)
tag_thread (pivot only with thread_id and tag_id)

如何制定一个查询，给出最近 100 个条目中出现次数最多的 5 个标签的名称？

Answer 1

这将为您提供最新 100 个主题的前 5 个标签

select ta.tag_name
from tags ta 
join tag_thread tt on tt.tag_id = ta.tag_id
join 
(
   select * from threads order by thread_id desc limit 100
) th on tt.thread_id = th.thread_id
group by ta.tag_name
order by count(tt.thread_id) desc
limit 5