根据 Teradata 中的条件优先级填充列

Question

我需要根据条件优先级填充列：

如果 O_M 不为零（例如：0.34），我检查同一列中的 Prev. record（按 TP_N 排序）O_M，如果用代码 (OD03,OT03,MO03) 编码的 3 个或更多实例为零，那么我应该用当前 O_M 值 - 0.34 填充 To_Compute 列。我需要对按 TP_N 排序的每个分区 (DT,MNTH,P_ID,A_BR,D_BR,B_BR,DR) 重复此操作。我应该只从 O_N - (OD03,OT03,MO03)

列中寻找这些代码

DT        MNTH  P_ID    A_BR    D_BR B_BR   TP_N    DR  O_M O_N  TO_Compute
9/29/2016   9   QT21    1506    05Y XS-123  487,006 0   0   ?       0
9/29/2016   9   QT21    1506    05Y XS-123  487,007 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,008 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,009 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,010 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,011 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,012 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,013 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,014 0   0   MO03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,015 0   0   OT03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,016 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,017 0   0.34    ?   0.34
9/29/2016   9   QT21    1506    05Y XS-123  487,018 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,019 0   1.03    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,020 0   0.3     ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,021 0   1.25    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,022 0   0   OP04    0
9/29/2016   9   QT21    1506    05Y XS-123  487,023 0   10.53   ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,024 0   0.37    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,025 0   0.28    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,026 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,027 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,028 0   0.6     ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,029 0   0.38    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,030 0   0.4 ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,031 0   0.35    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,032 0   0.45    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,033 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,034 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,035 0   0   OD03    0
9/29/2016   9   QT21    1506    05Y XS-123  487,036 0   0.3     ?   0.3
9/29/2016   9   QT21    1506    05Y XS-123  487,037 0   0.35    ?   0
9/29/2016   9   QT21    1506    05Y XS-123  487,038 0   0.52    ?   0

但是，如果 O_M 不为零（例如：0.6 - O_M 列从底部开始的第 11 行），我检查同一列中的 Prev. record O_M 并且我只有 2 个 prev 记录为 zero（对于使用代码 (OD03,OT03,MO03) 编码的 3 个或更多实例，那么我应该用 0 填充 To_Compute 列。

如果 O_M 不为零（例如：0.3 O_M 的倒数第三行），我检查同一列中的 Prev. record O_M在这里，对于使用代码 (OD03,OD03,OD03) 编码的 3 个或更多实例，它为零，那么我应该使用当前 O_M 值 - 0.3 填充 To_Compute 列。

我是TD的新手。对此有任何帮助。

Answer 1

未经测试，但根据您的描述应该可行：

case
   when sum(O_M) -- previous three rows are all 0 (assuming no negative values exist)
        over (partition by ??
              order by TP_N
              rows between 3 preceding and 1 preceding) = 0
    and -- prvious three rows contain any of the searched codes
        sum(case when O_N IN ('OD03','OT03','MO03') then 1 else 0 end)
        over (partition by ??
              order by TP_N
              rows between 3 preceding and 1 preceding) = 3
   then O_M
   else 0
end

Answer 2

我将提供两种可能的解决方案，供您决定哪种最适合您的情况。第一个更简单，但更乏味，因为它只是连接同一个 table 3 次。假设您上面的数据存在于 DATASET table:

select ds1.dt
,ds1.mnth
,ds1.p_id
,ds1.a_br
,ds1.d_br
,ds1.b_br
,ds1.tp_n
,ds1.dr
,ds1.o_m
,ds1.o_n
,case when zeroifnull(ds4.o_m) + zeroifnull(ds3.o_m) + zeroifnull(ds2.o_m) = 0 and ds4.o_n in ('OD03','OT03','MO03') and ds3.o_n in ('OD03','OT03','MO03') and ds2.o_n in ('OD03','OT03','MO03') then ds1.o_m
else 0 end as TO_COMPUTE
from dataset ds1
left join dataset ds2
on ds1.tp_n = ds2.tp_n +1
and ds1.dt = ds2.dt
and ds1.mnth = ds2.mnth
and ds1.p_id = ds2.p_id
and ds1.a_br = ds2.a_br
and ds1.d_br = ds2.d_br
and ds1.b_br = ds2.b_br
and ds1.dr = ds2.dr
left join dataset ds3
on ds1.tp_n = ds3.tp_n +2
and ds1.dt = ds3.dt
and ds1.mnth = ds3.mnth
and ds1.p_id = ds3.p_id
and ds1.a_br = ds3.a_br
and ds1.d_br = ds3.d_br
and ds1.b_br = ds3.b_br
and ds1.dr = ds3.dr
left join dataset ds4
on ds1.tp_n = ds4.tp_n +3
and ds1.dt = ds4.dt
and ds1.mnth = ds4.mnth
and ds1.p_id = ds4.p_id
and ds1.a_br = ds4.a_br
and ds1.d_br = ds4.d_br
and ds1.b_br = ds4.b_br
and ds1.dr = ds4.dr
order by 7;

第二个在子查询中使用分区：

select sub.dt
,sub.mnth
,sub.p_id
,sub.a_br
,sub.d_br
,sub.b_br
,sub.tp_n
,sub.dr
,sub.o_m
,sub.o_n
,case when o_m2 = 0 and o_m3 = 0 and o_m4 = 0 and o_n2 in ('OD03','OT03','MO03') and o_n4 in ('OD03','OT03','MO03') and o_n4 in ('OD03','OT03','MO03') then sub.o_m
else 0 end as TO_COMPUTE
from
(
select ds.dt
,ds.mnth
,ds.p_id
,ds.a_br
,ds.d_br
,ds.b_br
,ds.tp_n
,ds.dr
,ds.o_m
,ds.o_n
,max(ds.o_m) over (partition by ds.dt, ds.mnth, ds.p_id, ds.a_br, ds.d_br, ds.b_br, ds.dr order by ds.tp_n rows between 1 preceding and 1 preceding) as O_M2
,max(ds.o_m) over (partition by ds.dt, ds.mnth, ds.p_id, ds.a_br, ds.d_br, ds.b_br, ds.dr order by ds.tp_n rows between 2 preceding and 2 preceding) as O_M3
,max(ds.o_m) over (partition by ds.dt, ds.mnth, ds.p_id, ds.a_br, ds.d_br, ds.b_br, ds.dr order by ds.tp_n rows between 3 preceding and 3 preceding) as O_M4
,max(ds.o_n) over (partition by ds.dt, ds.mnth, ds.p_id, ds.a_br, ds.d_br, ds.b_br, ds.dr order by ds.tp_n rows between 1 preceding and 1 preceding) as O_N2
,max(ds.o_n) over (partition by ds.dt, ds.mnth, ds.p_id, ds.a_br, ds.d_br, ds.b_br, ds.dr order by ds.tp_n rows between 2 preceding and 2 preceding) as O_N3
,max(ds.o_n) over (partition by ds.dt, ds.mnth, ds.p_id, ds.a_br, ds.d_br, ds.b_br, ds.dr order by ds.tp_n rows between 3 preceding and 3 preceding) as O_N4
from dataset ds
) sub
order by 7;

根据 Teradata 中的条件优先级填充列

Populate a column based on conditional precedence in Teradata

teradata

operator-precedence

partition