[英]different conditions on different groups
我有一张这样的桌子。 我想获得按ID分组的第一行,其中acc1不为null,并且如果acc1中的所有行均为null,那么我想获取所有行。
id acc1 acc2
1 null 1
1 1 1
1 1 2
1 2 2
2 null 1
2 null 2
2 null 3
2 null 4
我想得到这样的输出:
id acc1 acc2
1 1 1
2 null 1
2 null 2
2 null 3
2 null 4
假设acc1
在不为null
时是唯一的(对于每个id):
select t.*
from (select t.*,
rank() over (partition by id
order by (case when acc1 is null then 2 else 1 end), acct1
) as seqnum
from t
) t
where seqnum = 1;
如果不是唯一的,那么这需要做更多的工作:
select t.*
from (select t.*,
row_number() over (partition by id
order by acct1, acct2
) as seqnum,
count(acct1) over (partition by id) as cnt
from t
) t
where seqnum = 1 or cnt = 0;
假定“第一”基于acct1
, acct2
。 SQL表本质上是无序的,因此您需要一列来指定顺序。
SELECT *
FROM mytable
QUALIFY Max(acc1) Over (PARTITION BY id) IS NULL -- only NULLs
OR Row_Number() Over (PARTITION BY id -- or the first non-null value
ORDER BY acc1 NULLS LAST) = 1
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