题解 | #考试分数(四)#
考试分数(四)
https://www.nowcoder.com/practice/502fb6e2b1ad4e56aa2e0dd90c6edf3c
SELECT job,
FLOOR((COUNT(1) + 1) / 2) start,
FLOOR(COUNT(1) / 2 + 1) end
FROM grade
GROUP BY job
ORDER BY job
-- 3个数 start = 2,end = 2
-- 4个数 statr = 2,end = 3
-- start = (n + 1) / 2
-- end = n / 2 + 1
除法向下取整
start = (n + 1) / 2
end = n / 2 + 1
