如何獲得顯示當前行ID和先前行ID之間的減法結果的列表？

Question

我怎樣才能在MS SQL表ID列表以數字顯示，我有「ORDER BY ID DESC」當前行的ID和前行的ID - 假設之間的差異

SELECT ID, ???? AS [CurrentID - PreviousID] 
FROM foo 
ORDER BY foo.ID DESC 

Answer 1

SELECT 
    ID, 
    ID - coalesce(
       (select max(ID) from foo foo2 where foo2.id<foo.id) 
       , 0) as Diff 
FROM foo 
ORDER BY foo.ID DESC 

http://sqlfiddle.com/#!3/1f21eb/3

Answer 2

嘗試以下查詢中使用CTE和row_number()：

Fiddle Demo

create table foo (id int) 

insert into foo values 
(1),(5),(8),(9) 

;with cte as (
    select Id, row_number() over (order by id desc) rn 
    from foo 
) 
select c1.id, c1.id-c2.id as [currentId - previousId] 
from cte c1 
     left join cte c2 on c1.rn = c2.rn - 1 
order by c1.rn 

| ID | CURRENTID - PREVIOUSID | 
------------------------------- 
| 9 |      1 | 
| 8 |      3 | 
| 5 |      4 | 
| 1 |     (null) |