ROW_Number 与自定义组

Question

我正在尝试 row_number 基于自定义分组，但我无法生成它。

下面是我的查询

CREATE TABLE mytbl (wid INT, id INT)
INSERT INTO mytbl Values(1,1),(2,1),(3,0),(4,2),(5,3)

当前输出

查询

SELECT *, RANK() OVER(PARTITION BY wid, CASE WHEN id = 0 THEN 0 ELSE 1 END ORDER BY ID)
FROM mytbl

我想根据自定义条件对行进行排名，例如如果 ID 为 0，则我开始新组，直到 ID 为非 0。

预期输出

wid     id  RN
1        1  1
2        1  1
3        0  1
4        2  2
5        3  2

Answer 1

如果我理解正确的话，你可以使用下一种方法。请注意，您需要有一个排序列（我假设这是 wid 列）：

声明：

;WITH ChangesCTE AS (
    SELECT 
        *,
        CASE WHEN LAG(id) OVER (ORDER BY wid) = 0 THEN 1 ELSE 0 END AS ChangeIndex
    FROM mytbl
), GroupsCTE AS (
    SELECT 
        *,
        SUM(ChangeIndex) OVER (ORDER BY wid) AS GroupIndex
    FROM ChangesCTE
)
SELECT 
    wid,
    id,
    DENSE_RANK() OVER (ORDER BY GroupIndex) AS Rank
FROM GroupsCTE

结果：

wid id  Rank
1   1   1
2   1   1
3   0   1
4   2   2
5   3   2

Answer 2

这里猜测，因为我们没有太多的澄清，但也许是这样：

SELECT wid,
       id,
       COUNT(CASE id WHEN 0 THEN 1 END) OVER (ORDER BY wid ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING) +1 AS [Rank]
FROM mytbl ;

Answer 3

没有对所需的逻辑做太多说明，我的理解是你想在 id = 0

时将 Rank 增加 1

select  wid, id, 
        [Rank]  = sum(case when id = 0 then 1 else 0 end) over(order by wid) 
                + case when id <> 0 then 1 else 0 end
from    mytbl

Answer 4

试试这个，

CREATE TABLE #mytbl (wid INT, id INT)
INSERT INTO #mytbl Values(1,1),(2,1),(3,0)
,(4,2),(5,3),(6,0),(7,4),(8,5),(9,6)

;with CTE as
(
select *,ROW_NUMBER()over(order by wid)rn 
from #mytbl where id=0

)
,CTE1 as
(
select max(rn)+1 ExtraRN from CTE
)
select a.* ,isnull(ca.rn,ca1.ExtraRN) from #mytbl a
outer apply(select top 1 * from CTE b 
where a.wid<=b.wid )ca
cross apply(select ExtraRN from CTE1)ca1


drop table #mytbl

这里OUTER APPLY和CROSS APPLY都不会增加cardianilityestimate.It总是return只有一行

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