题解 | 输出播放量最高的视频（妙用累加函数）
输出播放量最高的视频
https://www.nowcoder.com/practice/9e9cb264e1f64e28846975d5a32ba8e4
SELECT
cid,
MAX(uv) max_peak_uv
FROM
(SELECT
cid,
SUM(mark)OVER(PARTITION BY cid ORDER BY time) uv
FROM
(SELECT
cid,
start_time as time,
1 as mark
FROM play_record_tb t1
UNION ALL
SELECT
cid,
end_time as time,
-1 as mark
FROM play_record_tb t2) t3) t4
GROUP BY cid
ORDER BY max_peak_uv DESC, cid
LIMIT 3
，不说了，我又接了一单