一道hive面试题（窗口函数）

表student中的数据格式如下：

name month degree

s1 201801 A
s1 201802 A
s1 201803 C
s1 201804 A
s1 201805 A
s1 201806 A
s2 201801 A
s2 201802 B
s2 201803 C
s2 201804 A
s2 201805 D
s2 201806 A
s3 201801 C
s3 201802 A
s3 201803 A
s3 201804 A
s3 201805 B
s3 201806 A

现要查询表中连续三个月以上degree均为A的记录

 

 select
     a1.name,
     a1.month,
     a1.degree
 from
 (
     select
         name,
         month,
         degree,
         sum(if(degree = 'A', 1, 0)) OVER(PARTITION BY name ORDER BY month ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) AS score1,
         sum(if(degree = 'A', 1, 0)) OVER(PARTITION BY name ORDER BY month ROWS BETWEEN 1 PRECEDING AND 1 following) AS score2,
         sum(if(degree = 'A', 1, 0)) OVER(PARTITION BY name ORDER BY month ROWS BETWEEN  CURRENT ROW AND 2 following) AS score3
     from student
 ) as a1
 where
     a1.score1 = 3 or
     a1.score2 = 3 or
     a1.score3 = 3