September 30, 2012 at 8:06 am
I am having an issue trying to wrap my head around this.
I am trying to get the count of something over the days in a date range, but I don't need a per day count, I need the count of items for each day through the date range... does that make sense?
For example... the output should look something like this.
Day1 - 12
Day2 - 18
Day3 - 24
Day4 - 32
Day5 - 80
So, on Day1, there were 12 items. On Day2 there were 6 additional, so 12+6. On Day3 there were 6, so 12+6+6, Day4 there were 8, so 12+6+6+8, Day5 there were 48, so 12+6+6+8+48.
I am sure there is a way, but I can't wrap my head around it.
September 30, 2012 at 11:51 pm
This article by Jeff Moden gives you arguably the best way to approach the running totals problem:
http://www.sqlservercentral.com/articles/T-SQL/68467/
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St
October 1, 2012 at 2:48 am
May be this query will help your problem
CREATE TABLE #Temp (Name varchar(100), value int)
INSERT INTO #Temp
SELECT 'Day1', 12
UNION
SELECT 'Day2' ,6
UNION
SELECT 'Day3' , 10
UNION
SELECT 'Day4' ,8
UNION
SELECT 'Day5' ,4
;with cte as
(
select *, ROW_NUMBER() over(PARTITION by null order by Name ) as Id
FROM #Temp
)
SELECT b.Name , SUM(A.value ), B.Id
FROM cte A
INNER JOIN cte B on A.Id <= B.Id
GROUP BY B.Name , b.id
October 1, 2012 at 2:52 am
Sony Francis @EY (10/1/2012)
May be this query will help your problemCREATE TABLE #Temp (Name varchar(100), value int)
INSERT INTO #Temp
SELECT 'Day1', 12
UNION
SELECT 'Day2' ,6
UNION
SELECT 'Day3' , 10
UNION
SELECT 'Day4' ,8
UNION
SELECT 'Day5' ,4
;with cte as
(
select *, ROW_NUMBER() over(PARTITION by null order by Name ) as Id
FROM #Temp
)
SELECT b.Name , SUM(A.value ), B.Id
FROM cte A
INNER JOIN cte B on A.Id <= B.Id
GROUP BY B.Name , b.id
I believe Jeff talks about this "triangular join" in the article I referenced.
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St
October 1, 2012 at 6:37 am
I believe Jeff talks about this "triangular join" in the article I referenced.
I don't think that its a triangular join - no subquery really.
It looks like a moficifation of the CROSS JOIN method of running total computation.
Instead of a filtered CROSS JOIN, the INNER JOIN condition is expanded.
This is something that Jeff did not cover in his article as far as I can remember.
This is my understanding; I'm open to correction.
October 1, 2012 at 6:54 am
diamondgm (10/1/2012)
I believe Jeff talks about this "triangular join" in the article I referenced.
I don't think that its a triangular join - no subquery really.
It looks like a moficifation of the CROSS JOIN method of running total computation.
Instead of a filtered CROSS JOIN, the INNER JOIN condition is expanded.
This is something that Jeff did not cover in his article as far as I can remember.
This is my understanding; I'm open to correction.
You're correct. It's not a "triagular join". It's worse. It's a full accidental cross join. Look at the execution plan. You have 5 rows of data but one of the arrows coming off the table has 25 rows. If you add one more row to the data, that arrow jumps to 36, as expected with a cross join.
--Jeff Moden
Change is inevitable... Change for the better is not.
October 1, 2012 at 9:15 am
Great thanks... now that I understand what I am looking for (the running total part), I see that there is a bunch of information out there.
Thanks again.
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