SQL:查找列值匹配的行之间的差异

时间:2012-10-02 09:58:42

标签: sql sql-server sql-server-2008

抱歉,如果我的标题没有正确描述我正在尝试执行的任务。

对于大学项目,我收到了一个网站的访问日志,我已经丢弃了不需要的列并将其浓缩为:

╔══════════╦══════════════════════╦═════════════════╦═════════════╦════════════════╗
║ accessid ║ date_time_in_seconds ║ yg_requester_id ║ referent_id ║ referent_docid ║
╠══════════╬══════════════════════╬═════════════════╬═════════════╬════════════════╣
║     2449 ║        2009011621830 ║           32276 ║       12648 ║              1 ║
║     2776 ║        2009011622726 ║           76360 ║       11070 ║              1 ║
║     2804 ║        2009011622783 ║           32276 ║       13845 ║              1 ║
║     2894 ║        2009011623025 ║           32276 ║        7222 ║              1 ║
║     2895 ║        2009011623037 ║           32276 ║        1530 ║              1 ║
║     3000 ║        2009011623406 ║           32276 ║        3728 ║              1 ║
║     3019 ║        2009011623497 ║          520060 ║       10356 ║              1 ║
║     3245 ║        2009011625780 ║          300841 ║        4607 ║              1 ║
║     3274 ║        2009011628309 ║          532664 ║       14377 ║              1 ║
║     3275 ║        2009011628420 ║          532664 ║        9097 ║              1 ║
╚══════════╩══════════════════════╩═════════════════╩═════════════╩════════════════╝

最初时间和日期戳是每单位测量的单独列(年,月,日,小时,分钟,秒),为了便于计算,我将它们合并到date_time_in_seconds,其格式为

[0000][00][00][00000]
[YEAR][MONTH][DAY][Number of Seconds since 00:00]

accessid是表条目ID,yg_requester_id是网站访问者的唯一ID,referent_id是他们读取的网站文章的ID,referent_docid表示文章的类型,但此任务不需要。

基本上,我希望能够找到时间差,因为同一个yg_requester_id访问了最后一个不同的referent_id。 例如,查看上表中的这部分行:

╔══════════╦══════════════════════╦═════════════════╦═════════════╦════════════════╗
║ accessid ║ date_time_in_seconds ║ yg_requester_id ║ referent_id ║ referent_docid ║
╠══════════╬══════════════════════╬═════════════════╬═════════════╬════════════════╣
║     2449 ║        2009011621830 ║           32276 ║       12648 ║              1 ║
║     2776 ║        2009011622726 ║           76360 ║       11070 ║              1 ║
║     2804 ║        2009011622783 ║           32276 ║       13845 ║              1 ║
╚══════════╩══════════════════════╩═════════════════╩═════════════╩════════════════╝

yg_requester_id 32276在 06:03:50 (午夜后 21830 秒)访问了ID 12648 的文章)他们于2009年1月16日访问了 06:19:43 22783 的 13845 文章。在2009年1月16日午夜后的几秒钟内。因此可以安全地假设用户阅读了第一篇文章(id 12648 )约15分50秒

我想要找到的是同一用户访问的文章之间的时差。用户读取的连续文章可能没有连续的accessid(尽管它总是递增)。我还想把读取的时间限制在大约一个小时,因为任务是过滤掉读取的时间 可变分钟数(例如15)的记录。

在此先感谢,如果需要更多信息,请与我们联系

2 个答案:

答案 0 :(得分:2)

我会使用ROW_NUMBER对结果集进行yg_requester_id分区,并按accessid或datetime排序(假设您要将date_time_in_seconds列更改为常规日期时间列,如评论中所示。 然后我会通过请求者和前一个记录将结果集与自己一起加入,并获得差异。

让我尝试在没有正确数据的情况下编写查询:

SELECT X1.yg_requester_id, DATEDIFF(SECOND, X1.NewDateTimeField, X2.NewDateTimeField) AS TimeDifferenceInSeconds, X1.referent_id AS NewArticle, X2.referent_id AS FormerArticle
FROM
(
SELECT ROW_NUMBER() OVER(PARTITION BY yg_requester_id ORDER BY NewDateTimeField DESC) AS Position, NewDateTimeField, yg_requester_id, referent_id
FROM YourTable

) X1
INNER JOIN 
(
SELECT ROW_NUMBER() OVER(PARTITION BY yg_requester_id ORDER BY NewDateTimeField DESC) AS Position, NewDateTimeField, yg_requester_id, referent_id
FROM YourTable  
) X2 ON X2.yg_requester_id = X1.yg_requester_id AND X2.Position = X1.Position - 1

答案 1 :(得分:0)

此查询应检索请求者,指示对象以及请求者对指示对象所用的时间差(以秒为单位):

select abc.A_requestor as requestor_id,abc.B_refer as referent_id,abc.A_datetime-abc.B_datetime as time_difference   from 
(select a.accessid as A_accessid ,b.accessid as B_accessid,
a.yg_requestor_id as A_requestor,a.date_time_in_seconds as A_datetime,a.referent_id as A_refer,
b.yg_requestor_id as B_requestor,b.date_time_in_seconds as B_datetime,b.referent_id as B_refer
from weblog a
inner join weblog b
on a.yg_requestor_id = b.yg_requestor_id
and a.date_time_in_seconds > b.date_time_in_seconds
and a.referent_id != b.referent_id) abc

inner join 

(select cte.B_accessid,min(cte.A_accessid) as C_accessid from
(select a.accessid as A_accessid ,b.accessid as B_accessid,
a.yg_requestor_id as A_requestor,a.date_time_in_seconds as A_datetime,a.referent_id as A_refer,
b.yg_requestor_id as B_requestor,b.date_time_in_seconds as B_datetime,b.referent_id as B_refer
from weblog a
inner join weblog b
on a.yg_requestor_id = b.yg_requestor_id
and a.date_time_in_seconds > b.date_time_in_seconds
and a.referent_id != b.referent_id) cte 
group by cte.B_accessid ) xyz

on xyz.B_accessid = abc.B_accessid and xyz.C_accessid = abc.A_accessid