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ROW_NUMBERとPARTITION BYを使用して最初と最後の行を取得する

入力例

_Name | Value | Timestamp
-----|-------|-----------------
One  | 1     | 2016-01-01 02:00
Two  | 3     | 2016-01-01 03:00
One  | 2     | 2016-01-02 02:00
Two  | 4     | 2016-01-03 04:00
_

望ましい出力

_Name | Value | EarliestTimestamp | LatestTimestamp
-----|-------|-------------------|-----------------
One  | 2     | 2016-01-01 02:00  | 2016-01-02 02:00
Two  | 4     | 2016-01-01 03:00  | 2016-01-03 04:00
_

試行されたクエリ

最新のNameとValueを取得するためにROW_NUMBER()と_PARTITION BY_を使用しようとしていますが、最古の最新のTimestampも必要です値：

_SELECT
    t.Name,
    t.Value,
    t.????????? AS EarliestTimestamp,
    t.Timestamp AS LatestTimestamp
FROM 
    (SELECT
        ROW_NUMBER() OVER (PARTITION BY Name ORDER BY TIMESTAMP DESC) AS RowNumber,
        Name,
        Value
        Timestamp) t
WHERE t.RowNumber = 1
_
sqlsql-servertsqlwindow-functionsrow-number
9
Muhammad Rehan Saeed

これは、ウィンドウ関数minおよびmaxを使用して実行できます。

select distinct name, 
min(timestamp) over(partition by name), max(timestamp) over(partition by name)
from tablename

例

編集：コメントに基づく

select t.name,t.value,t1.earliest,t1.latest
from t 
join (select distinct name, 
      min(tm) over(partition by name) earliest, max(tm) over(partition by name) latest
      from t) t1 on t1.name = t.name and t1.latest = t.tm

編集：別のアプローチはfirst_valueウィンドウ関数。サブクエリと結合の必要性を排除します。

select distinct
name, 
first_value(value) over(partition by name order by timestamp desc) as latest_value,
min(tm) over(partition by name) earliest,
-- or first_value can be used 
-- first_value(timestamp) over(partition by name order by timestamp)
max(tm) over(partition by name) latest
-- or first_value can be used
-- first_value(timestamp) over(partition by name order by timestamp desc)
from t
5
Vamsi Prabhala

[〜＃〜] min [〜＃〜] および [〜＃〜] max [〜＃〜] 関数+ OUTER APPLY を使用できます=：

SELECT  t.Name, 
        p.[Value],
        MIN(t.[Timestamp]) as EarliestTimestamp ,
        MAX(t.[Timestamp]) as LatestTimestamp
FROM Table1 t
OUTER APPLY (SELECT TOP 1 * FROM Table1 WHERE t.Name = Name ORDER BY [Timestamp] DESC) p
GROUP BY t.Name, p.[Value]

出力：

Name    Value   EarliestTimestamp   LatestTimestamp
One     2       2016-01-01 02:00    2016-01-02 02:00
Two     4       2016-01-01 03:00    2016-01-03 04:00
1
gofr1

次のように、MIN(Timestamp) OVER (PARTITION BY Name)列に加えてROW_NUMBER()を使用します。

SELECT
    t.Name,
    t.Value,
    t.EarliestTimestamp AS EarliestTimestamp,
    t.Timestamp AS LatestTimestamp
FROM 
    (SELECT
        ROW_NUMBER() OVER (PARTITION BY Name ORDER BY TIMESTAMP DESC) AS RowNumber,
        MIN(Timestamp) OVER (PARTITION BY Name) AS EarliestTimestamp,
        ^^
        Name,
        Value
        Timestamp) t
WHERE t.RowNumber = 1
1
Chitharanjan Das

あなたの質問を理解したら、次のようにrow_number()関数を使用します。

SELECT  
    t.Name,  
    t.Value,  
    min(t.Timestamp) Over (Partition by name) As EarliestTimestamp,  
    t.Timestamp AS LatestTimestamp  
FROM   
    (SELECT ROW_NUMBER() OVER (PARTITION BY Name ORDER BY TIMESTAMP DESC) AS     RowNumber,  
        Name,  
        Value,  
        Timestamp) t  
WHERE t.RowNumber = 1  
Group By t.Name, t.Value, t.TimeStamp
0
Aldo López

シンプルに考えてください。

select 
    t.Name, 
    MAX(t.Value), 
    MIN(t.Timestamp), 
    MAX(t.Timestamp) 
FROM 
    t
group by 
    t.Name
0
NEER

あなたの質問を正しく理解している場合、row_number関数を2回使用する1つのオプションを次に示します。次に、それらを同じ行に配置するには、conditional aggregationを使用できます。

これは近いはずです：

SELECT
    t.Name,
    t.Value,
    max(case when t.minrn = 1 then t.timestamp end) AS EarliestTimestamp,
    max(case when t.maxrn = 1 then t.timestamp end) AS LatestTimestamp
FROM 
    (SELECT
        ROW_NUMBER() OVER (PARTITION BY Name ORDER BY TIMESTAMP) as minrn,
        ROW_NUMBER() OVER (PARTITION BY Name ORDER BY TIMESTAMP DESC) as maxrn,
        Name,
        Value
        Timestamp
     FROM YourTable) t
WHERE t.minrn = 1 or t.maxrn = 1
GROUP BY t.Name, t.Value
0
sgeddes