题解 | #考试分数(四)#

#本人愚解
select
 job
,case
when mod(count(job),2)=1 then round(count(job)/2,0)
when mod(count(job),2)=0 then floor(count(job)/2)
end as start
, case
when mod(count(job),2)=1 then round(count(job)/2,0)
when mod(count(job),2)=0 then floor(count(job)/2)+1
else 0
end as end
from
(select
job
,score
from grade
group by 1,2) a
group by 1
order by 1;


#大神解法
SELECT job, 
    floor(( count(*) + 1 )/ 2 ) AS "start", 
    floor(( count(*) + 2 )/ 2 ) AS 'end' 
FROM grade 
GROUP BY job 
ORDER BY job