最大递归已用尽

Question

我需要一种有效的方法来传入参数 [StartingNumber] 并从 [StartingNumber] 依次计数，直到找到丢失的数字。

我使用下面的sql来获取下一个数字：

      DECLARE @StartOffset int
        SET  @StartOffset = 23
        ; With Missing as (
            select @StartOffset as N where not exists(
    select * from [QUEUE] where QueueNum = @StartOffset AND ismelutash = 1)
        ), Sequence as 
    (       select @StartOffset as N from [QUEUE] where QueueNum = @StartOffset 
            union all
            select b.QueueNum from [QUEUE] b inner join Sequence s 
on b.QueueNum = s.N + 1 and b.ismelutash = 1
        )
        select COALESCE((select N from Missing),(select MAX(N)+1 from Sequence))

它已经工作了一段时间，但现在当我运行它时，我得到 '语句终止。在语句完成之前，最大递归 100 已用完。'

有人有什么想法吗？谢谢

编辑：

我添加了 maxrecursion 但它只是加载而不返回数据：

DECLARE @StartOffset int
SET  @StartOffset = 50

DECLARE @isMelutash int
SET @isMelutash = 0


; With QueueFilters as (
    select queuenum from queue where ismelutash = 1
),  Missing as (
    select @StartOffset as N where not exists(select * from QueueFilters where queuenum = @StartOffset)
), Sequence as (
    select @StartOffset as N from QueueFilters  where queuenum = @StartOffset
    union all
    select b.queuenum from QueueFilters  b inner join Sequence s on b.queuenum = s.N + 1
)
select COALESCE((select N from Missing ),(select MAX(N)+1 from Sequence ) )
**OPTION(MAXRECURSION 150)**

Answer 1

您可以在当前代码中使用MAXRECURSION 选项

但是，不需要逐行递归（使用 Itzik Ben-Gan 的方法）。这将检测 Queue 上也没有 ismelutash = 1 行的情况，因为它使用 Tally 表作为参考序列

;WITH
  Pass0 as (select 1 as C union all select 1), --2 rows
  Pass1 as (select 1 as C from Pass0 as A, Pass0 as B),--4 rows
  Pass2 as (select 1 as C from Pass1 as A, Pass1 as B),--16 rows
  Pass3 as (select 1 as C from Pass2 as A, Pass2 as B),--256 rows
  Pass4 as (select 1 as C from Pass3 as A, Pass3 as B),--65536 rows
  Pass5 as (select 1 as C from Pass4 as A, Pass4 as B),--4,294,967,296 rows
  Tally as (select row_number() over(order by C) as Number from Pass5)
 select TOP 1
    Number 
 from 
    Tally T
    LEFT JOIN   --corrected, oops.
    [QUEUE] Q ON T.Number = Q.QueueNum AND Q.ismelutash = 1
 where
    T.Number >= @StartOffset AND T.Number <= 1000000
    AND
    Q.QueueNum IS NULL
 ORDER BY
    T.Number

编辑：

带有 MAXRECURSION 提示的原始代码结尾。 This link 也更好

      DECLARE @StartOffset int
        SET  @StartOffset = 23
        ; With Missing as (
            select @StartOffset as N where not exists(
    select * from [QUEUE] where QueueNum = @StartOffset AND ismelutash = 1)
        ), Sequence as 
    (       select @StartOffset as N from [QUEUE] where QueueNum = @StartOffset 
            union all
            select b.QueueNum from [QUEUE] b inner join Sequence s 
on b.QueueNum = s.N + 1 and b.ismelutash = 1
        )
        select COALESCE((select N from Missing),(select MAX(N)+1 from Sequence))
        OPTION (MAXRECURSION 0)

Answer 2

我相信这是等价的，并且它不使用递归：

    SELECT COALESCE(MIN(QueueNum)
        , (SELECT Max(QueueNum) + 1
            FROM [Queue] 
            WHERE QueueNum > @StartOffset)
        , @StartOffset)
    FROM [QUEUE]
    WHERE QueueNum >= @StartOffset
    AND ismelutash != 1