元組的重複頻率

Question

ID    Date 
7019730   16-03-2015 
7019721   16-03-2015 
7020250   16-03-2015 
7219750   08-04-2015 
7019730   22-03-2015 
7019721   25-03-2015 
7019730   28-03-2015 
7019721   30-03-2015 

對於上面的表格，我想提取多長時間發生的ID與日期之間的差異作爲另一列。我的意思是輸出應該是這樣的：

ID    Date   Occurrence Frequency 
7019730   16-03-2015   1  0 
7019721   16-03-2015   1  0 
7020250   16-03-2015   1  0 
7219750   08-04-2015   1  0 
7019730   22-03-2015   2  6 
7019721   25-03-2015   2  9 
7019730   29-03-2015   3  7 
7019721   30-03-2015   3  5 

Answer 1

下面是一種方法。假設您的輸入表名稱爲D：

declare @d1 table(x bigint, y bigint, id int, dt date); 

insert @d1 (x, y, id, dt) 
select 
    row_number() over (order by id, [date]) x, 
    (row_number() over (order by id, [date]) - 1) y, 
    id, 
    [date] 
from 
    D 
order by 
    id, [date]; 

select * 
from (
    select 
     a.id, 
     a.dt, 
     row_number() over (partition by a.id order by a.id) as occurence, 
     coalesce(datediff(day, b.dt, a.dt), 0) as frequency 
    from @d1 a 
     left outer join @d1 b 
     on a.y = b.x 
     and a.id = b.id 
    ) as results 
order by occurence, id