with a as( select answer_date, round(count(issue_id)/count(distinct author_id),2) as per_num from answer_tb group by answer_date order by answer_date ) select * from a
with a as( select answer_date, round(count(issue_id)/count(distinct author_id),2) as per_num from answer_tb group by answer_date order by answer_date ) select * from a