根据案例陈述从分组中选择

基于这样的表,我想按PRODID分组,然后根据case语句选择一行。案例陈述是,如果IND1 = 1选择行,否则,如果IND2 = 1选择行,否则选择最大DATE的行。如果组中的多个指标为1,则选择行,指标组中的最大日期为1。

PRODID   IND1       IND2       DATE
---------------------------------------------------
1          1         0      4/24/2020
1          0         0      1/2/2020
1          1         0      1/1/2020
2          0         1      4/24/2020
2          0         1      1/1/2020
3          0         0      4/24/2020
3          0         0      1/1/2020
4          1         0      2/2/2020
4          0         1      4/24/2020
4          0         1      4/24/2020
PRODID   IND1       IND2       DATE
---------------------------------------------------
1          1         0      4/24/2020
2          0         1      4/24/2020
3          0         0      4/24/2020
4          1         0      2/2/2020
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笑狠徦
笑狠徦

One method uses row_number():

select t.*
from (select t.*,
             row_number() over (partition by prodid
                                order by (case when ind1 > 0 then 1 else 2 end),
                                         (case when ind1 = 0 and ind2 > 0 then 1 else 2 end),
                                         date desc
                               ) as seqnum

      from t
     ) t
where seqnum = 1;

如果您喜欢算术,可以将其简化为:

select t.*
from (select t.*,
             row_number() over (partition by prodid
                                order by ind1 desc, ind2 * (1 - ind1) desc, date desc
                               ) as seqnum

      from t
     ) t
where seqnum = 1;

请注意,将逻辑组合在一起的一个技巧是确保在以下情况下使用第一行:

1       0      0      2020-01-21
1       1      0      2020-01-20
1       1      1      2020-01-19

This is why you can't use order by ind1 desc, ind2 desc, date desc (which is quite tempting).

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