从序列中为配置单元中的每个值查找缺失的数字

Posted 2023-03-23

【中文标题】从序列中为配置单元中的每个值查找缺失的数字

【英文标题】：Find missing number from a sequence for each value in hive

【发布时间】：2020-05-09 14:33:54

【问题描述】：

我有一张如下表-

User-id  |  sequence
1   0
1   1
1   2
2   1
3   2

这里 0 1 和 2 是用户最多可以拥有的固定序列，现在我想要一个标志为 N，其中任何序列都缺少用户，否则标志应该是 Y。我可以说输出应该像 -

1   0  Y
1   1  Y
1   2  Y
2   0  N
2   1  Y
2   2  N
3   0  N
3   1  N
3   2  Y

【参考方案1】：

选择不同的user_id，与序列（0、1、2）交叉连接以获取所有用户+序列组合，与您的表左连接以计算标志

select us.user_id, 
       us.sequence,
       case when t.user_id is null then 'N' else 'Y' end flag
from
  (--all user sequence combinations
   select u.user_id, s.sequence
     from (select distinct user_id from mytable) u 
          cross join (select stack (3, 0, 1, 2) as sequence) s
  ) us --all user+sequence         
  left join mytable t on us.sequence=t.sequence and us.user_id=t.user_id
 order by us.user_id, us.sequence;

演示与您的数据示例：

with 
mytable as ( --use your table instead of this
select stack(5,
1, 0,
1, 1,
1, 2,
2, 1,
3, 2) as  (user_id,sequence)
)

select us.user_id, 
       us.sequence,
       case when t.user_id is null then 'N' else 'Y' end flag
from
(--all user sequence combinations
select u.user_id,
       s.sequence
  from (select distinct user_id from mytable) u 
       cross join (select stack (3, 0, 1, 2) as sequence) s
) us --all user+sequence         
 left join mytable t on us.sequence=t.sequence and us.user_id=t.user_id
  order by us.user_id, us.sequence;

结果：

user_id sequence flag
1   0   Y
1   1   Y
1   2   Y
2   0   N
2   1   Y
2   2   N
3   0   N
3   1   N
3   2   Y