具有日期 window 保留时间的 MAX 解析函数

Question

我正在尝试获取前几行 window 的最大日期。值得注意的是日期的实际时间部分。

实际 table 包含更多日期的数据，但查询位于一个函数中，该函数将日期作为参数以将数据限制为一天。

+---------------------------------------------------------------------+
¦FROM  ¦ TO    ¦ GRAPH                                                ¦
+------+-------+------------------------------------------------------¦
¦09:00 ¦ 11:00 ¦  [--------]                                          ¦
¦10:00 ¦ 10:30 ¦     [-]                                              ¦
¦10:45 ¦ 12:00 ¦         [-------]                                    ¦
¦13:00 ¦ 14:30 ¦                      [--------]                      ¦
¦14:00 ¦ 15:00 ¦                            [-----]                   ¦
¦15:30 ¦ 16:30 ¦                                      [----]          ¦
¦16:30 ¦ 17:30 ¦                                           [-----]    ¦
+---------------------------------------------------------------------+

-- show the time portion when querying, for convenience
alter session set nls_date_format = 'DD/MM/YYYY HH24:MI';

-- create an inline view with some data, perform select on it
with iv_dates (start_dt, end_dt) as ( 
select to_date('08/07/2016 09:00','DD/MM/YYYY HH24:MI'), to_date('08/07/2016 11:00','DD/MM/YYYY HH24:MI') from dual 
union all 
select to_date('08/07/2016 10:00','DD/MM/YYYY HH24:MI'), to_date('08/07/2016 10:30','DD/MM/YYYY HH24:MI') from dual 
union all 
select to_date('08/07/2016 10:30','DD/MM/YYYY HH24:MI'), to_date('08/07/2016 12:00','DD/MM/YYYY HH24:MI') from dual 
union all 
select to_date('08/07/2016 13:00','DD/MM/YYYY HH24:MI'), to_date('08/07/2016 14:30','DD/MM/YYYY HH24:MI') from dual 
union all 
select to_date('08/07/2016 14:00','DD/MM/YYYY HH24:MI'), to_date('08/07/2016 15:00','DD/MM/YYYY HH24:MI') from dual 
union all 
select to_date('08/07/2016 15:30','DD/MM/YYYY HH24:MI'), to_date('08/07/2016 16:30','DD/MM/YYYY HH24:MI') from dual 
union all 
select to_date('08/07/2016 16:30','DD/MM/YYYY HH24:MI'), to_date('08/07/2016 17:30','DD/MM/YYYY HH24:MI') from dual 
) 
 SELECT start_dt 
      , end_dt 
      , MAX (end_dt) OVER ( ORDER BY start_dt asc 
                            RANGE BETWEEN UNBOUNDED PRECEDING 
                            AND     1     PRECEDING 
                          )  
                          max_end_dt
 FROM iv_dates;

但是，我没有得到最大值 end_dt...

的任何结果

+--------------------------------------------------+
¦ START_DT         ¦ END_DT           ¦ MAX_END_DT ¦
+------------------+------------------+------------¦
¦ 08/07/2016 09:00 ¦ 08/07/2016 11:00 ¦ -          ¦
¦ 08/07/2016 10:00 ¦ 08/07/2016 10:30 ¦ -          ¦
¦ 08/07/2016 10:30 ¦ 08/07/2016 12:00 ¦ -          ¦
¦ 08/07/2016 13:00 ¦ 08/07/2016 14:30 ¦ -          ¦
¦ 08/07/2016 14:00 ¦ 08/07/2016 15:00 ¦ -          ¦
¦ 08/07/2016 15:30 ¦ 08/07/2016 16:30 ¦ -          ¦
¦ 08/07/2016 16:30 ¦ 08/07/2016 17:30 ¦ -          ¦
+--------------------------------------------------+

不过只要我添加另一天的日期，它就会开始 "working"

+--------------------------------------------------------+
¦ START_DT         ¦ END_DT           ¦ MAX_END_DT       ¦
+------------------+------------------+------------------¦
¦ 08/07/2016 09:00 ¦ 08/07/2016 11:00 ¦ -                ¦
¦ 08/07/2016 10:00 ¦ 08/07/2016 10:30 ¦ -                ¦
¦ 08/07/2016 10:30 ¦ 08/07/2016 12:00 ¦ -                ¦
¦ 08/07/2016 13:00 ¦ 08/07/2016 14:30 ¦ -                ¦
¦ 08/07/2016 14:00 ¦ 08/07/2016 15:00 ¦ -                ¦
¦ 08/07/2016 15:30 ¦ 08/07/2016 16:30 ¦ -                ¦
¦ 08/07/2016 16:30 ¦ 08/07/2016 17:30 ¦ -                ¦
¦ 09/07/2016 09:00 ¦ 09/07/2016 11:00 ¦ 08/07/2016 11:00 ¦
¦ 09/07/2016 10:00 ¦ 09/07/2016 10:30 ¦ 08/07/2016 11:00 ¦
¦ 09/07/2016 10:30 ¦ 09/07/2016 12:00 ¦ 08/07/2016 12:00 ¦
+--------------------------------------------------------+

只是为了说明这一点 - 我不需要分区，我只希望它能在我的数据上工作一天。

但是 windowing 子句似乎因为日期数据类型而表现不同。我不想要那样 - 我只是希望它根据排序在实际的前一行上工作，而不是在 (date - 1) 上工作。是因为这是约会吗，我该如何处理？

Answer 1

如果您正在使用 ORDER BY start_dt asc range BETWEEN UNBOUNDED PRECEDING 1 PRECEDING Oracle 计算当前行的逻辑偏移量。例子。对于示例的第一行，范围是 08/07/2016 09:00 和 07/07/2016 09:00 因为 (start_dt - 1) = 08/07/2016 09:00 -1 = 07/07/2016 09:00。 . 将范围更改为行

具有日期 window 保留时间的 MAX 解析函数

MAX analytic function with date window preserving time

sql

oracle

oracle11g

window-functions