题解 | 某乎问答回答过教育类问题的用户里有多少用户回答过职场类问题
某乎问答回答过教育类问题的用户里有多少用户回答过职场类问题
https://www.nowcoder.com/practice/b02cf9ee7b9f4cdda308f8155ff3415d
with c as (select distinct author_id from answer_tb a left join issue_tb b on a.issue_id=b.issue_id where b.issue_type = "Education" ) select count(author_id) num from answer_tb a left join issue_tb b on a.issue_id=b.issue_id where b.issue_type = "Career" and author_id in (select * from c)