Question

我正在使用vertica并在窗口上使用min（）窗口函数。但是，该函数似乎对某些窗口工作正常，但对于某些窗口，它在同一窗口中返回不同的最小值。有什么我在忽视

 select visid_high, visid_low, visit_num, date_time, visit_page_num,
         min(visit_page_num) over (partition by visid_high , visid_low , visit_num order by date_time)  as min_hotelinfo
from prd_omniture_hit_data_all  where pagename='Hotel Info - Home' and date(Date_time)='2016-06-19' order by visid_high, visid_low, visit_num, date_time

这适用于某些窗口并返回结果如下

visid_high  visid_low   visit_num   date_time   visit_page_num  min_hotelinfo
1000025785676989783 3541599610445607061 1   6/19/2016 8:54  2   2
1000025785676989783 3541599610445607061 1   6/19/2016 8:55  4   2
1000025785676989783 3541599610445607061 1   6/19/2016 8:55  5   2

visid_high  visid_low   visit_num   date_time   visit_page_num  min_hotelinfo
1000334043872452151 13928857828543794490    1   6/19/2016 14:56 2   2
1000334043872452151 13928857828543794490    1   6/19/2016 14:57 6   2
1000334043872452151 13928857828543794490    1   6/19/2016 14:57 7   2
1000334043872452151 13928857828543794490    2   6/19/2016 16:09 2   2
10006241273945967252    17961652664059791311    1   6/19/2016 20:09 2   2
10006241273945967252    17961652664059791311    1   6/19/2016 20:09 4   2
10006241273945967252    17961652664059791311    1   6/19/2016 20:10 8   2

但是，对于某些窗口，它无法正常运行

visid_high  visid_low   visit_num   date_time   visit_page_num  min_hotelinfo
10007599756616641840    269931436307846555  2   6/19/2016 19:51 2   2
10007599756616641840    269931436307846555  2   6/19/2016 19:52 3   2
10007599756616641840    269931436307846555  2   6/19/2016 19:52 5   2
10007599756616641840    269931436307846555  2   6/19/2016 19:53 7   2
10007599756616641840    269931436307846555  2   6/19/2016 19:53 9   2
10007599756616641840    269931436307846555  2   6/19/2016 19:53 10  **10**

10009683770139214971    14890994612952617462    2   6/19/2016 8:03  5   5
10009683770139214971    14890994612952617462    2   6/19/2016 8:03  7   **5**
10009683770139214971    14890994612952617462    2   6/19/2016 8:09  26  **26**
10009683770139214971    14890994612952617462    2   6/19/2016 8:12  28  26
10009683770139214971    14890994612952617462    2   6/19/2016 8:13  30  26
10009683770139214971    14890994612952617462    2   6/19/2016 8:14  32  26
10009683770139214971    14890994612952617462    2   6/19/2016 8:15  36  26
10009683770139214971    14890994612952617462    2   6/19/2016 8:17  40  26


visid_high  visid_low   visit_num   date_time   visit_page_num  min_hotelinfo
10012413883034897266    8201606845758098188 1   6/19/2016 7:22  4   4
10012413883034897266    8201606845758098188 1   6/19/2016 7:24  5   4
10012413883034897266    8201606845758098188 1   6/19/2016 7:24  8   4
10012413883034897266    8201606845758098188 1   6/19/2016 7:24  7   4
10012413883034897266    8201606845758098188 1   6/19/2016 7:24  6   **4**
10012413883034897266    8201606845758098188 1   6/19/2016 8:04  16  **16**
10012413883034897266    8201606845758098188 1   6/19/2016 8:06  20  16
10012413883034897266    8201606845758098188 1   6/19/2016 8:06  25  16
10012413883034897266    8201606845758098188 1   6/19/2016 8:07  28  16
10012413883034897266    8201606845758098188 1   6/19/2016 8:07  30  16

Answer 1

订购窗口，以便分区正确组合在一起。

controller.expire_fragment(key)

另外，可能不希望以这种方式强制转换Date_time。最好避免在谓词上进行转换和函数，以便数据库可以更好地进行优化（不是它会，但你会给它更多的机会）。

select visid_high, visid_low, visit_num, date_time, visit_page_num,
       min(visit_page_num) over 
         (partition by visid_high, visid_low, visit_num 
          order by visid_high, visid_low, visit_num) as min_hotelinfo
from prd_omniture_hit_data_all  
where pagename = 'Hotel Info - Home' 
and date(Date_time) = '2016-06-19' 
order by visid_high, visid_low, visit_num, date_time

vertica中的min（）窗口函数无法正常工作 - 为同一窗口返回不同的值

1 个答案: