Question

我对Impala / hive查询非常陌生，我不太清楚如何制作这个。

此查询的目标是获取定义范围的数据（完成条件的2个点）。

为了更清楚，我们有一个包含3列的表：Date，A和B.

我们按日期对表格进行排序，我们希望从两个A = 1之间的所有区间中获取所有行，其中没有任何B = 1。（因此，范围介于每两个A = 1之间，条件是它们中没有B = 1）。

我描绘了我正在寻找的概念，因此它变得更加清晰。

链接：https://drive.google.com/open?id=0B_zAJFzI2slWQnRwN2gwWk9NSG8

Answer 1

select  dt,A,B

from   (select  dt,A,B
               ,max (case when A=1 then dt end) over p  as p_A1_dt
               ,max (case when B=1 then dt end) over p  as p_B1_dt
               ,min (case when A=1 then dt end) over f  as f_A1_dt
               ,min (case when B=1 then dt end) over f  as f_B1_dt

        from    mytable

        window  p as (order by dt rows between unbounded preceding and 1 preceding)
               ,f as (order by dt rows between 1 following and unbounded following)
        ) t

where   (   p_A1_dt >= p_B1_dt
        or  (   p_A1_dt is not null
            and p_B1_dt is null
            )
        )

    and (   f_A1_dt <= f_B1_dt
        or  (   f_A1_dt is not null
            and f_B1_dt is null
            )
        ) 

    and coalesce(A,-1) <> 1

相同，但没有window decleration

select  dt,A,B

from   (select  dt,A,B
               ,max (case when A=1 then dt end) over (order by dt rows between unbounded preceding and 1 preceding)  as p_A1_dt
               ,max (case when B=1 then dt end) over (order by dt rows between unbounded preceding and 1 preceding)  as p_B1_dt
               ,min (case when A=1 then dt end) over (order by dt rows between 1 following and unbounded following)  as f_A1_dt
               ,min (case when B=1 then dt end) over (order by dt rows between 1 following and unbounded following)  as f_B1_dt

        from    mytable
        ) t

where   (   p_A1_dt >= p_B1_dt
        or  (   p_A1_dt is not null
            and p_B1_dt is null
            )
        )

    and (   f_A1_dt <= f_B1_dt
        or  (   f_A1_dt is not null
            and f_B1_dt is null
            )
        ) 

    and coalesce(A,-1) <> 1

蜂巢/黑斑羚。查询以获取完成条件的范围中的行

1 个答案: