分区内的 Oracle SQL 顺序

Question

我有一个视图，其中结果按序列的降序返回。结果集中的一列是 correlation_id ，这对于一堆行是相同的。我希望按照创建时间戳的顺序在 correlation_id 的分区内应用排序。


Data:
---------------------------
SEQ | CORRELATION_ID | CR_TIMESTAMP
9   | Z              | 22/FEB/16 03:00:19.191000000 PM
8   | Z              | 22/FEB/16 02:00:26.577000000 PM
7   | Z              | 22/FEB/16 01:07:58.171000000 PM
6   | A              | 22/FEB/16 03:07:58.171000000 PM
5   | A              | 22/FEB/16 02:07:58.171000000 PM

What I want is maintain original order, only sort within the partition by CR_TIMESTAMP:
---------------------------
SEQ | CORRELATION_ID | CR_TIMESTAMP                    | SRLNO 
7   | Z              | 22/FEB/16 03:07:58.171000000 PM | 1
8   | Z              | 22/FEB/16 02:00:26.577000000 PM | 2
9   | Z              | 22/FEB/16 01:07:58.171000000 PM | 3
5   | A              | 22/FEB/16 02:07:58.171000000 PM | 1
6   | A              | 22/FEB/16 03:07:58.171000000 PM | 2

I tried (without success) 
select V.*,  ROW_NUMBER()
    OVER (PARTITION BY CORRELATION_ID 
    ORDER BY CR_TIMESTAMP ASC) as SRLNO FROM A_VIEW V;

我的尝试结果为：最终结果按 CORRELATION_ID 的升序排列。即所有 A，然后所有 B，然后 .. 所有 Z。在每个分区内，排名正确地按 CR_TIMESTAMP 的顺序排列。

Answer 1

我是这样理解你的要求的：你首先要CORRELATION_ID Z，因为它的最高SEQ（9）高于A的最高SEQ（6），但是里面每个 CORRELATION_ID 您希望按日期排序的记录。

select seq, correlation_id, cr_timestamp
from mytable
order by max(seq) over (partition by correlation_id) desc, cr_timestamp desc;

分区内的 Oracle SQL 顺序

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