SQL查找首次出現

Question

我已經在這里待了大約一個小時，而且幾乎沒有任何進展 - 我以為我會來這里尋求幫助/建議。

所以，給出我的表樣本：

+-----------+-----------------------------+--------------+
| MachineID | DateTime                    | AlertType    |
+-----------+-----------------------------+--------------+
| 56        | 2015-10-05 00:00:23.0000000 | 2000         |
| 42        | 2015-10-05 00:01:26.0000000 | 1006         |
| 50        | 2015-10-05 00:08:33.0000000 | 1018         |
| 56        | 2015-10-05 00:08:48.0000000 | 2003         |
| 56        | 2015-10-05 00:10:15.0000000 | 2000         |
| 67        | 2015-10-05 00:11:59.0000000 | 3001         |
| 60        | 2015-10-05 00:13:02.0000000 | 1006         |
| 67        | 2015-10-05 00:13:08.0000000 | 3000         |
| 56        | 2015-10-05 00:13:09.0000000 | 2003         |
| 67        | 2015-10-05 00:14:50.0000000 | 1018         |
| 67        | 2015-10-05 00:15:00.0000000 | 1018         |
| 47        | 2015-10-05 00:16:55.0000000 | 1006         |
+-----------+-----------------------------+--------------+

我將如何得到第一次出現MachineID瓦特/一AlertType 2000和相同的最后一次出現MachineID瓦特/和AlertType 2003。

這是我嘗試過的 - 但它沒有輸出我的期望。

SELECT *
FROM [Alerts] a
where 
    DateTime >= '2015-10-05 00:00:00'
    AND  DateTime <= '2015-10-06 00:00:00'
    and not exists(
        select b.MachineID 
        from [Alerts] b
        where   b.AlertType=a.AlertType and
                b.MachineID<a.MachineID
    )
order by a.DateTime ASC

編輯： 上面的代碼沒有得到我想要的東西因為我沒有具體告訴它搜索AlertType = 2000或AlertType = 2003 ，但即使我嘗試了，我仍然無法收集我想要的結果。

這是我想要顯示的輸出：

+-----------+-----------------------------+--------------+
| MachineID | DateTime                    | AlertType    |
+-----------+-----------------------------+--------------+
| 56        | 2015-10-05 00:00:23.0000000 | 2000         |
| 56        | 2015-10-05 00:13:09.0000000 | 2003         |
+-----------+-----------------------------+--------------+

任何有關這方面的幫助將不勝感激！

Answer 1

不確定，但是：

select * from [Table] 
WHERE [DateTime] IN (
            SELECT MIN([DateTime]) as [DateTime] 
            FROM [Table] 
            WHERE AlertType = 2000 
            GROUP BY MachineId 
                UNION ALL 
            SELECT MAX([DateTime]) as [DateTime] 
            FROM [Table] 
            WHERE AlertType = 2003 
            GROUP BY MachineId)
ORDER BY MachineId, AlertType

Answer 2

您的外部部分看起來像2015-10-05到2015-10-06之間的所有記錄，其中包括按日期排序的所有記錄。 內部部分僅在沒有記錄符合外部日期范圍時發生。

看起來像GSazheniuk它是正確的，但我不確定你是否只想要2條記錄或所有匹配MachineID和兩個警報？

Answer 3

不確定您的嘗試與您的問題有什么關系，但要回答這個問題：

如何首次出現具有2000的AlertType和最后一次出現的相同MachineID w /和AlertType為2003的MachineID。

簡單：

SELECT * FROM (
    SELECT TOP 1 * FROM Alerts WHERE AlertType='2000' ORDER BY Datetime ASC
    UNION ALL 
    SELECT TOP 1 * FROM Alerts WHERE AlertType='2003' ORDER BY Datetime DESC
) t

Answer 4

我想每個人都錯過了你的警報類型不是決定因素，而是一個補充。 這應該可以滿足您的需求。 我走過了整個過程。 `IF OBJECT_ID（'tempdb ..＃alerts'）IS NOT NULL DROP表#alerts

    CREATE TABLE #alerts
    (
    MachineID int,
    dte DATETIME,
    alerttype int
    )
INSERT INTO #alerts VALUES ('56','20151005 00:00:23','2000')
INSERT INTO #alerts VALUES ('42','20151005 00:01:26','1006')
INSERT INTO #alerts VALUES ('50','20151005 00:08:33','1018')
INSERT INTO #alerts VALUES ('56','20151005 00:08:48','2003')
INSERT INTO #alerts VALUES ('56','20151005 00:10:15','2000')
INSERT INTO #alerts VALUES ('67','20151005 00:11:59','3001')
INSERT INTO #alerts VALUES ('60','20151005 00:13:02','1006')
INSERT INTO #alerts VALUES ('67','20151005 00:13:08','3000')
INSERT INTO #alerts VALUES ('56','20151005 00:13:09','2003')
INSERT INTO #alerts VALUES ('67','20151005 00:14:50','1018')
INSERT INTO #alerts VALUES ('67','20151005 00:15:00','1018')
INSERT INTO #alerts VALUES ('47','20151005 00:16:55','1006')
GO
WITH rnk as ( --identifies the order of the records. 
    Select 
        MachineID,
        dte = dte,
        rnk = RANK() OVER (partition BY machineid ORDER BY dte DESC) --ranks the machine ID's based on date (first to Last)
        FROM #alerts
        ),
    agg  as( --Pulls your first  and last record
    SELECT 
        MachineID,
        frst = MIN(rnk), 
        lst = MAX(rnk) 
    FROM rnk 
    GROUP BY MachineID
    )
SELECT
    pop.MachineID,
    pop.dte,
    pop.alerttype

FROM #alerts pop
JOIN rnk r ON pop.MachineID = r.MachineID AND pop.dte = r.dte --the date join allows you to hook into your ranks
JOIN agg ON pop.MachineID = agg.MachineID 
WHERE agg.frst = r.rnk OR agg.lst = r.rnk -- or clause can be replaced by two queries with a union all
ORDER BY 1,2 --viewability... machineID, date`

我個人使用交叉應用來執行這樣的任務，但是CTE對於這個練習來說更具視覺友好性。