题解 | #某乎问答高质量的回答中用户属于各级别的数量#

-- 高质量回答情况表中对应的用户等级
select 
level_cut 
,count(1) as num 
from (
select 
a.*
,(case 
when author_level <=2 then '1-2级' 
when author_level <=4 then '3-4级' 
else '5-6级' 
end) as level_cut 
from answer_tb a 
left join author_tb b 
on a.author_id = b.author_id 
where char_len >= 100 ) c 
group by level_cut 
order by num desc 

题目不难，但是需要注意审题。。。