I am using SQL Server 2014. I have a table like this
create table revenue (id varchar(2), trasdate date, revenue int);
insert into revenue(id, trasdate, revenue)
values ('aa', '2018/09/01', 1234.5),
('aa' , '2018/08/04', 450),
('aa', '2018/07/03',500),
('aa', '2018/06/04',600),
('ab', '2018/09/01', 1234.5),
('ab' , '2018/08/04', 450),
('ab', '2018/07/03',500),
('ab', '2018/06/04',600),
('ab', '2018/05/03', 200),
('ab', '2018/04/02', 150),
('ab', '2018/03/01', 350),
('ab', '2018/02/05', 700),
('aa', '2018/01/07', 400)
;
I am preparing a SQL query to create a SSRS report. I want to calculate a past 3 month average for current and every past 3rd month with result like below. As we are in month of September right now. The result should show something like this:
**id Period Revenue_3Mon**
aa March-May 233
aa June-Aug 516
ab March-May 233
ab June-Aug 516
Though I can figure out about the Period column. I was mainly focussing on getting the Revenue_3Mon. So I initially tried with the below query after some googling. But this query throws an error as incorrect syntax near 'rows' and if I remove rows from the query then it throws an error as Incorrect syntax near the keyword 'between'. And incorrect syntax near i.
select i.id,i.mon,
avg([i.mon_revenue]) over (partition by i.id, i.mon order by [i.id],
[i.mon] rows between 3 preceding and 1 preceding row) as revenue_3mon --
-- using 3 preceding and 1 preceding row you exclude the current row
from (select a.id, month(a.trasdate) as mon,
sum(a.revenue) as mon_revenue
from revenue a
group by a.id, month(a.trasdate)) i
group by i.id, i.mon
order by i.id,i.mon;
After few efforts, I gave up on this query and came up with new solution which was a bit close to my expectation (after lots of trial and errors).
Declare #count as int;
declare #max as int;
set #count = 4
declare #temp as table (id varchar(2), monthoftrasdate int, revenue int,
[3monavg] int);
SET #MAX = (SELECT distinct MAX(a.ROWNUM) FROM (SELECT id, month(trasdate)
as mon, SUM(revenue) TotalRevenue,
-- sum(revenue) as mon_revenue,
ROW_NUMBER() OVER(PARTITION BY ID ORDER BY MONTH(TRASDATE)) AS ROWNUM
FROM revenue
GROUP BY ID, MONTH(TRASDATE)
) A GROUP BY A.ID);
while (#count <= #max )
begin
WITH CTE AS (
SELECT id, month(trasdate) as mon, SUM(revenue) TotalRevenue,
-- sum(revenue) as mon_revenue,
ROW_NUMBER() OVER(PARTITION BY ID ORDER BY MONTH(TRASDATE)) AS
ROWNUM
FROM revenue
GROUP BY ID, MONTH(TRASDATE)
)
insert into #temp
SELECT A.ID,A.MON, a.TotalRevenue
,( SELECT avg(b.TotalRevenue) as avgrev
FROM CTE B
WHERE B.ROWNUM BETWEEN A.ROWNUM-3 AND A.ROWNUM-1
AND A.ID = B.ID --AND A.mon = B.mon
--and b.ROWNUM < a.ROWNUM
and (a.mon > 3 and a.ROWNUM > 3)
GROUP BY B.id
) AS REVENUE_3MON
FROM CTE A
set #count = #count + 1
end
select distinct a.* from #temp a
The reason I had to use 'distinct' is because the query was showing duplicate records for every id and every month. So far the result shows like below
id MonthofTrasdate Revenue 3MonAvg
aa 1 400 NULL
aa 2 700 NULL
aa 3 350 NULL
aa 4 150 483
aa 5 200 400
aa 6 600 233
aa 7 500 316
aa 8 450 433
aa 9 1234 516
ab 1 400 NULL
ab 2 700 NULL
ab 3 350 NULL
ab 4 150 483
ab 5 200 400
ab 6 600 233
ab 7 500 316
ab 8 450 433
ab 9 1234 516
This pulls out past 3 month average for every month. But i will just manipulate the rest on SSRS the way i want it.
As currently my table has no data for previous year. This works for me showing the appropriate result for next couple of months for now. But my concern is when I have to show my boss for next year Jan, Feb and March then it should be able to pull also for these months as well like Oct-Dec (Previous year), Nov-Jan and Dec - Feb. I am struggling to figure out the proper way to put this in my query.
Can you please help me out with this query? And also let me know what is wrong with my former query.
Problems with your first attempt:
You enclosed some of the aliases and column names in square brackets like [i.mon_revenue]. There is no need for square brackets, but if you want to use them, you have to break them up at the dot: [i].[mon_revenue].
In your window function expression, there is one row too many (in the end).
Window functions are applied at the very end (after the rest of the respective query), so you also have to include i.mon_revenue in your GROUP BY clause of the outer query.
Knowing that the inner query will produce one row per id and mon, there will never be preceding rows in an id-mon partition. Therefore, you must not partition by both, but only by id.
To simplify the query after resolving the issues: ordering by a partition column generally makes no sense, and since - as already mentioned - the inner query returns unique id-mon combinations, you don't have to group by these in the outer query. Looking at that query, we see that the outer query just directly selects and uses the values from the inner query, which makes a separation in two queries unneccessary. So, in fact, you wanted to perform the following query, which will produce the rolling 3-month average (I added the monthly TotalRevenue as well):
SELECT id, MONTH(trasdate) AS mon, SUM(revenue) AS TotalRevenue,
AVG(SUM(revenue)) OVER (PARTITION BY id ORDER BY MONTH(trasdate) ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING) AS revenue_3mon
FROM revenue
GROUP BY id, MONTH(trasdate)
ORDER BY id, MONTH(trasdate);
Suggestions on your second attempt:
When calculating the #MAX value, you rely on the fact that each id has revenues for the same number of months. Are you sure?
The code inside the WHILE loop does not depend on #count, so it will add the same data into the #temp table multiple times, which is probably the reason why you thought you needed a DISTINCT. Therfore: No need for the variables, no need for a loop and a #temp, no need for DISTINCT.
The conditions A.mon > 3 and A.rownum > 3 are redundant with your current data. In general, I guess, you don't want to explicitly excluse the months from January to March, so A.mon > 3 should be removed. A.rownum > 3 could be removed, too, unless you really don't want to see a 3-month average when there are only 2 preceding months or less.
As the subquery for the average is restricted to only one id, there's no need for a GROUP BY.
Since the ROW_NUMBER function doesn't care about gaps in the months, I suggest to use a different numbering function, for example DATEDIFF(month, MAX(trasdate), GETDATE()) AS mnum. Of course, the comparison in the WHERE clause of the subquery then has to be changed to B.mnum BETWEEN A.mnum+1 AND A.mnum+3.
So, your second attempt can be reduced to this, which will produce the same result as the above, at least with your sample data, where no gaps in the months exist:
WITH CTE AS (
SELECT id, MONTH(trasdate) AS mon, SUM(revenue) AS TotalRevenue,
DATEDIFF(month, MAX(trasdate), GETDATE()) AS mnum
FROM revenue
GROUP BY id, MONTH(trasdate)
)
SELECT id, mon, TotalRevenue
, (SELECT AVG(B.TotalRevenue)
FROM CTE B
WHERE B.mnum BETWEEN A.mnum+1 AND A.mnum+3
AND A.id = B.id
) AS revenue_3mon
FROM CTE A
ORDER BY id, mnum DESC;
Now, guess what, an expression like my mnum using DATEDIFF increases by one every month as we move to the past, regardless of a change of years, so this might be useful for grouping as well, whether you want to (or can?) use Window functions or not:
With OVER()
SELECT id, MONTH(MIN(trasdate)) AS mon, YEAR(MIN(trasdate)) AS yr, SUM(revenue) AS TotalRevenue,
AVG(SUM(revenue)) OVER (PARTITION BY id ORDER BY MIN(trasdate) ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING) AS revenue_3mon
FROM revenue
GROUP BY id, DATEDIFF(month, trasdate, GETDATE())
ORDER BY id, DATEDIFF(month, trasdate, GETDATE()) DESC;
Without OVER()
WITH CTE AS (
SELECT id, MIN(trasdate) AS min_dt, SUM(revenue) AS TotalRevenue,
DATEDIFF(month, trasdate, GETDATE()) AS mnum
FROM revenue
GROUP BY id, DATEDIFF(month, trasdate, GETDATE())
)
SELECT id, MONTH(min_dt) AS mon, YEAR(min_dt) AS yr, TotalRevenue
, (SELECT AVG(B.TotalRevenue)
FROM CTE B
WHERE B.mnum BETWEEN A.mnum+1 AND A.mnum+3
AND A.id = B.id
) AS revenue_3mon
FROM CTE A
ORDER BY id, mnum DESC;
Both queries allow for retrieving the minimum and maximum date for each period (including month and year).
If you instead wanted what you originally posted under The result should show something like this (just grouping by previous 3-months intervals), you just would have to group your original revenue table by id and (DATEDIFF(month, trasdate, GETDATE())-1)/3 (filtering WHERE DATEDIFF(month, trasdate, GETDATE()) > 0). If so, this kind of grouping and aggregation could, of course, be done also by the Report Server.
I think this should do what you want:
select r.*,
avg(r.mon_revenue) over (partition by r.id
order by r.mon_min
rows between 3 preceding and 1 preceding row
) as revenue_3mon
-- using 3 preceding and 1 preceding row you exclude the current row
from (select r.id, month(r.trasdate) as mon,
min(r.trasdate) as mon_min,
sum(r.revenue) as mon_revenue
from revenue r
group by r.id, year(r.trasdate), month(r.trasdate)
) 4
order by r.id, r.mon, r.mon_min;
Notes:
I fixed the code so it recognizes years as well as dates.
The expression [i.mon_revenue] is not a valid column reference (in your case). You have no column with the name "i.mon_revenue" (with the . in the name).
I changed the column alias to r to match the table.
I added a date column for each month to make it easier to express the ordering.
The outer group by is not necessary.
There are several syntax errors in your code. This should give you what you need. The inner query is the important bit but hopefully this will be enough to get you on your way.
I switch our the temp table for variable and changed the revenue column to not be INT as you have decimal values in there but other than that your original sample table is unchanged
DECLARE #revenue table (id varchar(2), trasdate date, revenue float)
insert into #revenue(id, trasdate, revenue)
values ('aa', '2018/09/01', 1234.5),
('aa' , '2018/08/04', 450),
('aa', '2018/07/03',500),
('aa', '2018/06/04',600),
('ab', '2018/09/01', 1234.5),
('ab' , '2018/08/04', 450),
('ab', '2018/07/03',500),
('ab', '2018/06/04',600),
('ab', '2018/05/03', 200),
('ab', '2018/04/02', 150),
('ab', '2018/03/01', 350),
('ab', '2018/02/05', 700),
('aa', '2018/01/07', 400)
SELECT
*
FROM
(
SELECT
*
, MONTH(trasdate) as MonthNumber
, AVG(revenue) OVER (PARTITION BY id
ORDER BY
id
, MONTH(trasdate) ROWS BETWEEN 3 PRECEDING AND 1 PRECEDING) as ThreeMonthAvg
FROM #revenue
) a
WHERE MONTH(GETDATE()) - MonthNumber IN (0, 3, 6, 9)
This gives the following results
aa 2018-06-04 600 6 400
aa 2018-09-01 1234.5 9 516.666666666667
ab 2018-03-01 350 3 700
ab 2018-06-04 600 6 233.333333333333
ab 2018-09-01 1234.5 9 516.666666666667
I have a table of events, called tbl_events that looks something like this:
PersonID Date
1 30/03/2015
1 22/04/2015
1 30/06/2015
2 18/07/2016
2 09/12/2016
2 28/04/2017
3 01/10/2014
3 28/11/2016
3 28/11/2016
3 16/01/2017
4 13/04/2017
4 09/05/2017
I want to be able to group these events up by the start date of each 'sequence', with a sequence being defined as a run of events from the first identified to the last identified for each PersonID. The last event in a sequence is defined as the event where thereafter there are no subsequent events for that PersonID for a year.
The result of this I would expect to look like is below:
PersonID FirstDate Sequence Events
1 30/03/2015 1 3
2 18/07/2016 1 3
3 01/10/2014 1 1
3 28/11/2016 2 3
4 13/04/2017 1 2
I am able to identify the sequences in Excel and pivot the data, but I need to be able to do this in SQL.
Here is the formula I have used in Excel to generate the sequence number (I am populating cell C3, with column A being PersonID and B being Date):
=+IF(A2<>A3,1,IF((B3-B2)<365,C2,C2+1))
I have joined the table back on itself using ROW_NUMBER to get the difference between the Date and the previous event date for that ID, but I'm not really sure where to go from there.
Any help is much appreciated.
My solution is based on the sample data you've provided along with your excel formula.
-- easily consumable sample data
DECLARE #tbl_events TABLE (PersonId int, [date] date)
INSERT #tbl_events VALUES
(1,'20150330'),(1,'20150422'),(1,'20150630'),(2,'20160718'),(2,'20161209'),(2,'20170428'),
(3,'20141001'),(3,'20161128'),(3,'20161128'),(3,'20170116'),(4,'20170413'),(4,'20170509');
-- Solution
WITH groupings AS
(
SELECT
PersonId,
FirstDate = MIN([date]) OVER (PARTITION BY personId ORDER BY [date]),
NextDate = LAG([date],1,[date]) OVER (PARTITION BY personId ORDER BY [date]),
[date],
grouper =
DATEDIFF(DAY, MIN([date]) OVER (PARTITION BY personId ORDER BY [date]), [date]) / 365
FROM #tbl_events
),
Prep AS
(
SELECT
PersonId,
firstDate = IIF(grouper = 0, FirstDate, IIF(FirstDate = NextDate, [date],NextDate))
FROM groupings
)
SELECT
PersonId,
FirstDate,
[Sequence] = ROW_NUMBER() OVER (PARTITION BY personId ORDER BY FirstDate),
[Events] = COUNT(*)
FROM prep
GROUP BY personId, FirstDate;
Results
PersonId FirstDate Sequence Events
----------- ---------- -------------------- -----------
1 2015-03-30 1 3
2 2016-07-18 1 3
3 2014-10-01 1 1
3 2016-11-28 2 3
4 2017-04-13 1 2
First note all years have 365 days, nonetheless, I'm using 365 to emulate your excel logic; this would need to be updated to account for leap years. Next, like your excel formula - this will only be correct when there are two sequences;
it would not work when, say personId has a date of jan 1 2015, then jan 10 2016, then feb 1 2017.Let us know if we need logic to accommodate for the aforementioned scenarios.
Lastly this solution uses LAG which requires SQL Server 2012+, if you're working with an earlier version of SQL the query will have to be updated accordingly.
I'm trying to query some transactional data to establish the CurrentProductionHours value for each Report at the end of each month.
Providing there has been a transaction for each report in each month, that's pretty straight-forward... I can use something along the lines of the code below to partition transactions by month and then pick out the rows where TransactionByMonth = 1 (effectively, the last transaction for each report each month).
SELECT
ReportId,
TransactionId,
CurrentProductionHours,
ROW_NUMBER() OVER (PARTITION BY [ReportId], [CalendarYear], [MonthOfYear]
ORDER BY TransactionTimestamp desc
) AS TransactionByMonth
FROM
tblSource
The problem that I have is that there will not necessarily be a transaction for every report every month... When that's the case, I need to carry forward the last known CurrentProductionHours value to the month which has no transaction as this indicates that there has been no change. Potentially, this value may need to be carried forward multiple times.
Source Data:
ReportId TransactionTimestamp CurrentProductionHours
1 2014-01-05 13:37:00 14.50
1 2014-01-20 09:15:00 15.00
1 2014-01-21 10:20:00 10.00
2 2014-01-22 09:43:00 22.00
1 2014-02-02 08:50:00 12.00
Target Results:
ReportId Month Year ProductionHours
1 1 2014 10.00
2 1 2014 22.00
1 2 2014 12.00
2 2 2014 22.00
I should also mention that I have a date table available, which can be referenced if required.
** UPDATE 05/03/2014 **
I now have query which is genertating results as shown in the example below but I'm left with islands of data (where a transaction existed in that month) and gaps in between... My question is still similar but in some ways a little more generic - What is the best way to fill gaps between data islands if you have the dataset below as a starting point?
ReportId Month Year ProductionHours
1 1 2014 10.00
1 2 2014 12.00
1 3 2014 NULL
2 1 2014 22.00
2 2 2014 NULL
2 3 2014 NULL
Any advice about how to tackle this would be greatly appreciated!
Try this:
;with a as
(
select dateadd(m, datediff(m, 0, min(TransactionTimestamp))+1,0) minTransactionTimestamp,
max(TransactionTimestamp) maxTransactionTimestamp from tblSource
), b as
(
select minTransactionTimestamp TT, maxTransactionTimestamp
from a
union all
select dateadd(m, 1, TT), maxTransactionTimestamp
from b
where tt < maxTransactionTimestamp
), c as
(
select distinct t.ReportId, b.TT from tblSource t
cross apply b
)
select c.ReportId,
month(dateadd(m, -1, c.TT)) Month,
year(dateadd(m, -1, c.TT)) Year,
x.CurrentProductionHours
from c
cross apply
(select top 1 CurrentProductionHours from tblSource
where TransactionTimestamp < c.TT
and ReportId = c.ReportId
order by TransactionTimestamp desc) x
A similar approach but using a cartesian to obtain all the combinations of report ids/months.
in the first step.
A second step adds to that cartesian the maximum timestamp from the source table where the month is less or equal to the month in the current row.
Finally it joins the source table to the temp table by report id/timestamp to obtain the latest source table row for every report id/month.
;
WITH allcombinations -- Cartesian (reportid X yearmonth)
AS ( SELECT reportid ,
yearmonth
FROM ( SELECT DISTINCT
reportid
FROM tblSource
) a
JOIN ( SELECT DISTINCT
DATEPART(yy, transactionTimestamp)
* 100 + DATEPART(MM,
transactionTimestamp) yearmonth
FROM tblSource
) b ON 1 = 1
),
maxdates --add correlated max timestamp where the month is less or equal to the month in current record
AS ( SELECT a.* ,
( SELECT MAX(transactionTimestamp)
FROM tblSource t
WHERE t.reportid = a.reportid
AND DATEPART(yy, t.transactionTimestamp)
* 100 + DATEPART(MM,
t.transactionTimestamp) <= a.yearmonth
) maxtstamp
FROM allcombinations a
)
-- join previous data to the source table by reportid and timestamp
SELECT distinct m.reportid ,
m.yearmonth ,
t.CurrentProductionHours
FROM maxdates m
JOIN tblSource t ON t.transactionTimestamp = m.maxtstamp and t.reportid=m.reportid
ORDER BY m.reportid ,
m.yearmonth
Please help me undestand how order by influences to over clause. I have read msdn and one book and still misunderstood.
Let's say we have such query:
SELECT Count(OrderID) over(Partition By Year(OrderDate))
,*
FROM [Northwind].[dbo].[Orders]
ORDER BY OrderDate
The result is that each raw has the column with the value how many entries in the table have the same year.
alt text http://img-fotki.yandex.ru/get/3912/svin80.2/0_3b871_3bb591da_XL
But what's happened when i try this query?:
SELECT ROW_NUMBER() over(Partition By Year(OrderDate)
order by OrderDate) as RowN
,*
FROM [Northwind].[dbo].[Orders]
ORDER BY RowN
alt text http://img-fotki.yandex.ru/get/3908/svin80.2/0_3b872_c9352fb1_XL
Now I see the only thing that each RowN has 3 different years for each value (1996, 1997, 1998). I expected that RowN will be the same value for all 1996 year dates. Please explain me what happens and why.
In this case:
SELECT ROW_NUMBER() over(Partition By Year(OrderDate)
order by OrderDate) as RowN,*
FROM [Northwind].[dbo].[Orders]
order by RowN
What you're seeing it it's giving you a row number that is partitioned by year, meaning that each year has it's own climbing row number. To make this a bit cleaerer in the results:
SELECT ROW_NUMBER() over(Partition By Year(OrderDate)
order by OrderDate) as RowN,*
FROM [Northwind].[dbo].[Orders]
order by RowN, Year(OrderDate)
This means that each year, say 1997, will have orders 1 through n ordered by the date that year...like this was the 1st order of 1997, 2nd order of 1997, etc.
The results will make far more sense if you do this:
SELECT
Year(OrderDate),
ROW_NUMBER() over(Partition By Year(OrderDate)order by OrderDate) as RowN,
*
FROM [Northwind].[dbo].[Orders]
ORDER BY Year(OrderDate), RowN
Now you can see that each year has increasing row numbers starting from 1, ordered by order date:
Year RowN Order Date
1997 1 10400 1997-01-01 00:00:00
1997 2 10401 1997-01-01 00:00:00
1997 3 10402 1997-01-02 00:00:00
...
1998 1 10808 1998-01-01 00:00:00
1998 2 10809 1998-01-01 00:00:00
1998 3 10810 1998-01-01 00:00:00
...