SQL transformed result
I have data in DB like this
INPUT
Id | Start Date | End Date | Value
1 1/2/2010 1/6/2010 20
2 1/5/2010 1/7/2010 80
I need to transform this data using sql query like this
OUTPUT
Id | Month | Value
1 1/2/2010 20
1 1/3/2010 20
1 1/4/2010 20
1 1/5/2010 20
1 1/6/2010 20
2 1/5/2010 80
2 1/6/2010 80
2 1/7/2010 80
Please suggest possible solution to take this. Consider performance as input table has million开发者_如何学Gos of records and we need to process all. I am using SQL 2008, and want to avoid loop or cursors. Thanks.
Have a look at using a recursive CTE query then.
Something like
DECLARE @Table TABLE(
Id INT,
StartDate DATETIME,
EndDate DATETIME,
Value FLOAT
)
INSERT INTO @Table SELECT 1,'1/2/2010','1/6/2010',20
INSERT INTO @Table SELECT 2,'1/5/2010','1/7/2010',80
;WITH Vals AS (
SELECT id,
StartDate,
EndDate,
Value
FROM @Table
UNION ALL
SELECT id,
StartDate + 1,
EndDate,
Value
FROM Vals
WHERE StartDate + 1 <= EndDate
)
SELECT *
FROM Vals
ORDER BY id,
StartDate
OPTION (MAXRECURSION 0)
Create a helper table Beta:
CREATE TABLE Beta (
Monat DATETIME,
)
fill it with all monthes you need:
INSERT INTO Beta VALUES( '1/1/2010' )
...
INSERT INTO Beta VALUES( '1/12/2010' ) ' maybe '12/1/2010'
and:
SELECT A.Id, B.Monat, A.Value
FROM <YourTable> A, Beta B
WHERE B.Monat >= A.StartDate And B.Monat <= A.EndDate
(no garanties wrt performance)
I did not anticipate that something like this has to be 'proven' -
===============================================================================
SO5192555 - select for hungryMind
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
SELECT * FROM Alpha
-------------------------------------------------------------------------------
|Id|StartDate|EndDate |Value|
| 1| 2/1/2010|6/1/2010| 20|
| 2| 5/1/2010|7/1/2010| 80|
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
SELECT A.Id, B.Monat, A.Value FROM Alpha A, Beta B WHERE B.Monat >= A.StartDate And B.Monat <= A.EndDate
-------------------------------------------------------------------------------
|Id|Monat |Value|
| 1|2/1/2010| 20|
| 1|3/1/2010| 20|
| 1|4/1/2010| 20|
| 1|5/1/2010| 20|
| 1|6/1/2010| 20|
| 2|5/1/2010| 80|
| 2|6/1/2010| 80|
| 2|7/1/2010| 80|
===============================================================================
xpladolib.vbs: Erfolgreich beendet. (0) [ 0.17969 secs ]
Despite hungryMind's "I can't" and "it seems", I still think that using the helper table is the right way to go:
Filling table Alpha with 50.000 records like
SELECT TOP 5 *, DATEDIFF("d", StartDate, EndDate ) + 1 AS Days FROM Alpha ORDER BY Id
-------------------------------------------------------------------------------
|Id|StartDate |EndDate |Value|Days|
| 1| 12/6/2001| 5/15/2002| 10| 161|
| 2| 8/2/2001 |10/27/2001| 20| 87|
| 3|10/28/2000| 6/17/2001| 30| 233|
| 4| 1/15/2000| 8/30/2000| 40| 229|
| 5| 3/25/2002|10/23/2002| 50| 213|
-------------------------------------------------------------------------------
SELECT TOP 5 *, DATEDIFF("d", StartDate, EndDate ) + 1 AS Days FROM Alpha ORDER BY Id DESC
-------------------------------------------------------------------------------
|Id |StartDate |EndDate |Value |Days|
|50000|10/31/2001| 5/6/2002 |500000| 188|
|49999| 8/31/2002|12/31/2002|499990| 123|
|49998| 4/11/2002|11/11/2002|499980| 215|
|49997| 3/13/2002|12/16/2002|499970| 279|
|49996| 7/4/2002 | 7/27/2002|499960| 24|
and creating the helper table Beta based on the range MIN( StartDate ) ... MAX( EndDate ) - I used a loop to insert all the 1297 days -
-----------------------------------------------
SELECT TOP 5 * FROM Beta ORDER BY Monat
-----------------------------------------------
|Monat |
|1/1/2000|
|1/2/2000|
|1/3/2000|
|1/4/2000|
|1/5/2000|
-----------------------------------------------
SELECT TOP 5 * FROM Beta ORDER BY Monat DESC
-----------------------------------------------
|Monat |
|7/20/2003|
|7/19/2003|
|7/18/2003|
|7/17/2003|
|7/16/2003|
and executing
SELECT A.Id, B.Monat, A.Value
INTO Gamma FROM Alpha A, Beta B
WHERE B.Monat >= A.StartDate And B.Monat <= A.E
to insert 7.522.243 records into table Gamma:
SELECT TOP 5 * FROM Gamma Order BY Id, Monat
-----------------------------------------------------------
|Id|Monat |Value|
| 1| 12/6/2001| 10| <--- | 1| 12/6/2001| 5/15/2002| 10| 161|
| 1| 12/7/2001| 10|
| 1| 12/8/2001| 10|
| 1| 12/9/2001| 10|
| 1|12/10/2001| 10|
-----------------------------------------------------------
SELECT TOP 5 * FROM Gamma Order BY Id DESC, Monat
-----------------------------------------------------------
|Id |Monat |Value |
|50000|10/31/2001|500000| <---- |50000|10/31/2001| 5/6/2002 |500000| 188|
|50000| 11/1/2001|500000|
|50000| 11/2/2001|500000|
|50000| 11/3/2001|500000|
|50000| 11/4/2001|500000|
took about 2 mins on my WinXP/SQLExpress/1 GB Mem/VirtualBox machine. Doing just the "SELECT INTO" took 26 secs.
50.000 source records are less than 113000 or 'millions', but I did my test using ADO/OleDB via VBScript. Surely a MS Server Admin can do better.
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