基於標識符在2個區間之間隔離數據

Question

我的一位朋友對我有這個問題，我感到太困惑了。

他的團隊正在加載DW，並且數據在adhoc基礎上以遞增和滿載的方式進行。現在有一個標識符標誌 ，表示滿載何時開始或停止。現在我們需要收集並分離所有滿負荷。

對於離：

create table #tmp (
    id int identity(1,1) not null, 
    name varchar(30) null, 
    val int null 
) 

insert into #tmp (name, val) select 'detroit', 3 
insert into #tmp (name, val) select 'california', 9 
insert into #tmp (name, val) select 'houston', 1 
insert into #tmp (name, val) select 'los angeles', 4 
insert into #tmp (name, val) select 'newyork', 8 
insert into #tmp (name, val) select 'chicago', 1 
insert into #tmp (name, val) select 'seattle', 9 
insert into #tmp (name, val) select 'michigan', 6 
insert into #tmp (name, val) select 'atlanta', 9 
insert into #tmp (name, val) select 'philly', 6 
insert into #tmp (name, val) select 'brooklyn', 8 

drop table #tmp 

規則是：

每當val爲9，全負荷啓動;每當val爲8時，全部的 加載停止; （或者當下一個val是8時，滿載停止）。

在這種情況下，對於全負載，我應該只收集這些記錄：

ID名稱VAL
3休斯敦1
4洛杉磯4
10費城6

我的方法到目前爲止：

;with mycte as (
    select id, name, val, row_number() over (order by id) as rnkst 
    from #tmp 
    where val in (8,9)) 
SELECT * 
FROM mycte y 
WHERE val = 9 
    AND Exists (
     SELECT * 
     FROM mycte x 
     WHERE x.id = 
         ----> this gives start 9 record but not stop record of 8 
         (SELECT MIN(id)  
         FROM mycte z 
         WHERE z.id > y.id) 
      AND val = 8) 

我不想冒險進入光標方式的光標，但用CTE，請指教！

UPDATE：
正如應答者，我重申了規則的人提到。
- >滿負荷記錄開始後即將9（第9條記錄不包括在內）
- >滿負荷持續到它看到眼前8.
- >所以，有效地9至8形式的所有記錄滿載的小塊
- >的個人第9個記錄本身沒有得到考慮，因爲它沒有8夥伴
- >下面顯示的結果集滿足這些條件

Answer 1

我不知道如果我的英語命令將允許我解釋一下我的方法完全，但我會嘗試，以防萬一它可以幫助。

1. 排列所有行並分別排列界限（val IN (8, 9)）。

2. 加入子集，其中val = 8與子集val = 9的條件是前者的綁定排名應該完全比後者的1（一）大。

3. 加入非(8, 9)行的子集到結果集步驟2的條件是下述（通用）排名應該是val = 9子集的排名和該val = 8之一之間。

這裏的查詢來說明我的口頭描述的嘗試：

WITH ranked AS (
    SELECT 
    *, 
    rnk  = ROW_NUMBER() OVER (ORDER BY id), 
    bound_rnk = ROW_NUMBER() OVER (
     PARTITION BY CASE WHEN val IN (8, 9) THEN 1 ELSE 2 END 
     ORDER BY id 
    ) 
    FROM #tmp 
) 
SELECT 
    load.id, 
    load.name, 
    load.val 
FROM  ranked AS eight 
INNER JOIN ranked AS nine ON eight.bound_rnk = nine.bound_rnk + 1 
INNER JOIN ranked AS load ON load.rnk BETWEEN nine.rnk AND eight.rnk 
WHERE eight.val = 8 
    AND nine .val = 9 
    AND load .val NOT IN (8, 9) 
; 

，你可能不相信我，但是當我測試了它，它沒有返回以下：

id name  val 
-- ----------- --- 
3 houston  1 
4 los angeles 4 
10 philly  6 

Answer 2

我不相信有是一種不需要一個while循環就可以做到這一點的方法，也可能是一個複雜的遞歸cte。所以，我的問題是，如果這完全有可能在代碼中完成？ SQL不像程序語言那樣強大，所以代碼會更好地處理這個問題。如果這不是一個選項，那麼我會去一個while循環（比遊標好得多）。我將很快創建SQL。

/* 
drop table #tmp 
drop table #finalTmp 
drop table #startStop 
*/ 

    create table #tmp (
    id int identity(1,1) not null, 
    name varchar(30) null, 
    val int null 
) 

insert into #tmp (name, val) select 'detroit', 3 
insert into #tmp (name, val) select 'california', 9 
insert into #tmp (name, val) select 'houston', 1 
insert into #tmp (name, val) select 'los angeles', 4 
insert into #tmp (name, val) select 'newyork', 8 
insert into #tmp (name, val) select 'chicago', 1 
insert into #tmp (name, val) select 'seattle', 9 
insert into #tmp (name, val) select 'michigan', 6 
insert into #tmp (name, val) select 'atlanta', 9 
insert into #tmp (name, val) select 'philly', 6 
insert into #tmp (name, val) select 'brooklyn', 8 

CREATE TABLE #Finaltmp 
    (
     id INT, 
     name VARCHAR(30), 
     val INT 
    ) 

    SELECT id, val, 0 AS Checked 
    INTO #StartStop 
    FROM #tmp 
    WHERE val IN (8,9) 

    DECLARE @StartId INT, @StopId INT 
    WHILE EXISTS (SELECT 1 FROM #StartStop WHERE Checked = 0) 
    BEGIN 
     SELECT TOP 1 @StopId = id 
     FROM #StartStop 
     WHERE EXISTS 
      --This makes sure we grab a stop that has a start before it 
      (
       SELECT 1 
       FROM #StartStop AS TestCheck 
       WHERE TestCheck.id < #StartStop.id AND val = 9 
      ) 
     AND Checked = 0 AND val = 8 
     ORDER BY id 

     --If no more starts, then the rest are stops 
     IF @StopId IS NULL 
      BREAK 

     SELECT TOP 1 @StartId = id 
     FROM #StartStop 
     WHERE Checked = 0 AND val = 9 
      --Make sure we only pick up the 9 that matches 
      AND Id < @StopId 
     ORDER BY Id DESC 

     IF @StartId IS NULL 
      BREAK 

     INSERT INTO #Finaltmp 
     SELECT * 
     FROM #tmp 
     WHERE id BETWEEN @StartId AND @StopId 
      AND val NOT IN (8,9) 

     --Make sure to "check" any values that fell in the middle (double 9's) 
     --If not, then you would start picking up overlap data 
     UPDATE #StartStop 
     SET Checked = 1 
     WHERE id <= @StopId 
    END 

    SELECT * FROM #Finaltmp 

我注意到，數據看上去有點靠不住的，所以我試圖把一些邊緣情況的檢查和評論對他們