题解 | #考试分数(四)#
考试分数(四)
http://www.nowcoder.com/practice/502fb6e2b1ad4e56aa2e0dd90c6edf3c
select
job
,case when medium = round(medium, 0) then round(medium,0) else round(medium+0.5,0) end as start # medium = round(medium,0)判断是否medium是小数,进而可以确定count(*)是奇数还是偶数，然后start和end分情况讨论
,case when medium = round(medium, 0) then round(medium+1,0) else round(medium+0.5,0) end as end
from (
select
job
,count(*)/2 medium
from grade
group by 1
) a
order by job;
