题解 | #某乎问答高质量的回答中用户属于各级别的数量#

SELECT
    case
    when b.author_level in (1,2) then '1-2级'
    when b.author_level in (3,4) then '3-4级'
    when b.author_level in (5,6) then '5-6级'
    else '' end as level_cut,
    count(issue_id) num
from answer_tb a
left join author_tb b
on a.author_id = b.author_id
where char_len >= 100
group by level_cut
order by num desc