Question

如果我有一张包含以下内容的表格：

user_id | event_time

如何计算事件之间的平均天数？得到类似的东西：

days_diff | count
        1 | 100
        2 | 90
        3 | 20

用户可能在事件之间有1天，但在后续事件之间也可能有3天。我如何在两个桶中统计它们？

示例数据（请注意，在这种情况下，DAY DIFF为0/1，但这只是一小部分数据）

user_id | event_time
82770 2015-05-04 02:34:53
1 2015-05-04 08:45:53
82770 2015-05-04 20:38:24
82770 2015-05-04 20:38:24
82770 2015-05-04 20:38:24
1 2015-05-05 09:31:42
82770 2015-05-05 13:33:36
82770 2015-05-05 13:33:53
1 2015-05-06 09:53:59
1 2015-05-06 23:31:18
1 2015-05-06 23:31:35
1 2015-05-07 12:31:41
82770 2015-05-07 16:01:16

Answer 1

这是一个不使用临时表的解决方案：

select daybetweenevents as days_diff,
   count(daybetweenevents) as count
from (select t1.user_id,
    t1.event_time,
    datediff(day, t1.event_time, min(t2.event_time)) as daybetweenevents
    from yourtable t1
    inner join yourtable t2
       on t1.user_id = t2.user_id
    and t1.event_time < t2.event_time
    group by t1.user_id, t1.event_time) temp
group by daybetweenevents

Answer 2

使用DATEDIFF和相关的子查询来获取上一个日期。

SELECT user_id, event_time, 
DATEDIFF((SELECT MAX(event_time) 
          FROM yourtable 
          WHERE event_time < a.event_time), event_time) AS days_diff
FROM yourtable AS a

Answer 3

我选择了一个有序用户事件的临时表，以便更轻松地进行相关性查找，并处理具有两个以上事件的用户。这应该可以为您提供所需的输出。

create table #tempOrderedUserEvents
(
id int identity (1,1),
userid int,
event_time datetime
)

insert into #tempOrderedUserEvents (userid, event_time)
select [user_id], event_time
from YourUserDataTable A
order by [user_id], event_time

select interval, count(*) as [count]
from
(
    select A.userid, datediff(day, A.event_time, B.event_time) as interval
    from #tempOrderedUserEvents A
    JOIN #tempOrderedUserEvents B on A.id+1 = B.id and A.userid = B.userid
) as Intervals
group by interval

drop table #tempOrderedUserEvents

计算事件之间的平均天数？

3 个答案: