mysql - 我想将 2 个 SQL 查询合并到一个查询中 - 带计数

Question

我有 2 张 table :

表 1:问题:

-Id
-Name
-AdditionalInformation
-Author
-QuestionCategory
-Date
-Time

表 2:注释:

- Id
- QuestionId

我需要得到Question中的所有表格以及每个QuestionID的评论数。

有人可以帮忙吗？

我尝试过的:

select * from Questions
union
SELECT Count(ID) FROM Comments Group By QuestionId

Answer 1

select q.*, c.commentCount
from questions q left join
     (select questionid, count(id) as commentCount
      from comments
      group by questionid
     ) c
     on c.questionid = q.id