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Inserting records; increment weekly

Looking for a function in SQL (2008) where I can repeatedly enter a new row, incrementing two date fields (by 7 days each time)...

Insert into MyTable Values (Field1, Field2, StartDate, EndDate)

With start date beginning at 02/04/2013, end date beginning at 2/10/2013 and both continuing until year-end (or so)...
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sirbounty
Asked:
sirbounty
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1 Solution
 
Ioannis ParaskevopoulosCommented:
You may use a cursor(for the repetition) and DATEADD function for the increment of the dates

Giannis
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sirbountyAuthor Commented:
cursor?
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Ioannis ParaskevopoulosCommented:
Here is a sample code:

DECLARE @MyTable Table
(
	StartDate DATETIME,
	EndDate DATETIME
)

DECLARE @InitialStartDate DATETIME
DECLARE @InitialENDDate DATETIME

DECLARE @StopDate DATETIME

SET	@InitialStartDate = '20130402'
SET	@InitialENDDate = '20131002'
SET	@StopDate = '20131231'


DECLARE @StartDate DATETIME
DECLARE @EndDate DATETIME

Insert into @MyTable Values (@InitialStartDate,@InitialENDDate)


DECLARE IncrementalInsert CURSOR FOR
SELECT	MAX(StartDate), MAX(EndDate)
FROM	@MyTable 

OPEN IncrementalInsert 
FETCH NEXT FROM 
IncrementalInsert 
INTO @StartDate, @EndDate

WHILE @StartDate<@StopDate
BEGIN 

	SET @StartDate = DATEADD(dd,7,@StartDate)
	SET @EndDate = DATEADD(dd,7,@EndDate)

	--INSERT INTO @MyTable Values ( @StartDate, @EndDate)
	SELECT * FROM @MyTable


	FETCH NEXT FROM IncrementalInsert INTO @StartDate, @EndDate
END 
 
CLOSE IncrementalInsert 
DEALLOCATE IncrementalInsert

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Giannis
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Ioannis ParaskevopoulosCommented:
In my scenario i create a table variable in order to store the dates. You don't need to do that as you already have the table, but my code is just a demonstration.

For simplicity i have only the date fields but you may have your other fields too.

Then i declare my starting dates and the date after which i need the loop to stop.

After that, i insert the first row and in the loop i insert the dates incremented by 7.

When my start date becomes greater than the 'StopDate' i quit the loop.

I hope it is clear what i am doing....

Giannis
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sirbountyAuthor Commented:
Still going through it, but that helps some.
When I run it, it doesn't seem to be incrementing as is.

I get the date setup, and the loop, but I'm not sure about the table setup.
In your example, you declare a table with only start & end dates.  
Would I add the other columns in my table to that (and their data types)?
How would I reference that to my actual table name?

Does this section

SELECT      MAX(StartDate), MAX(EndDate)
FROM      @MyTable

Actually state to grab what's already in the rows?  I'm okay with that method, just trying to understand the code...

I'm having trouble with the while definition as well...
WHILE @StartDate<@StopDate
StartDate will always be < StopDate, won't it?
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Ioannis ParaskevopoulosCommented:
The table variable is just to show you an example. You should actualy use your table.

The select max is to just get your starting dates if you actually have data in your table.

If you see every time you enter in the loop it increments the @StartDate so at some point it will be greater than the @StopDate.

Giannis
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Scott PletcherSenior DBACommented:
A "tally" table works great for that.  It's much faster than looping, and much easier to change.


DECLARE @startDate datetime
DECLARE @last_date_to_generate datetime

SET @startDate = '20130204' --<<-- change as needed
SET @last_date_to_generate = '20131231' --<<-- change as needed

;WITH
cteDigits AS (
    SELECT 0 AS digit UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL
    SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9
),
cteTally AS (
    SELECT [10s].digit * 10 + [1s].digit AS num
    FROM cteDigits [1s] -- 0-9
    CROSS JOIN cteDigits [10s] -- 00-99 (100 total)
    --can add more if need more than 100 values    
)
INSERT INTO dbo.MyTable ( field1, field2, startDate, endDate )
SELECT 'field1', 'field2', DATEADD(DAY, num * 7, @startDate), DATEADD(DAY, num * 7 + 6, @startDate)
FROM cteTally
WHERE
    num BETWEEN 0 AND DATEDIFF(DAY, @startDate, @last_date_to_generate) / 7 - 1
ORDER BY
    3
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sirbountyAuthor Commented:
That code gives me :Incorrect syntax near 'testdata'
on the line that reads:

INSERT INTO dbo.tblcollaboncall (NewID, startDate, endDate, 'testdata',1,0)
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sirbountyAuthor Commented:
Ah, took me a bit to figure it out, but that ended up being quick and simple once I got my head wrapped around it - thanx! :^)
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Scott PletcherSenior DBACommented:
Sweet!

If you need to read data from an existing table -- that is, take row(s) from an existing table and combine them with all the dates -- you can do this:


INSERT INTO dbo.MyTable ( field1, field2, startDate, endDate )
SELECT tn.field1, tn.field2, DATEADD(DAY, num * 7, @startDate), DATEADD(DAY, num * 7 + 6, @startDate)
FROM dbo.table_name tn
CROSS JOIN cteTally
WHERE
    num BETWEEN 0 AND DATEDIFF(DAY, @startDate, @last_date_to_generate) / 7 - 1
    --AND tn.col_name = 'some_value' AND ...
ORDER BY
    3
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