7 day average in SQL Server 2014 - sql

Question

I need to modify the following T-SQL statement to include a rolling 7 day average of the revenue.
What do I need to include in the following code to achieve that?
SELECT
CAST(create_dtg AS DATE) DATE,
SUM([agent_rev] + [anchor_rev] + [corp_rev] + [offsite_rev]) AS RevenueTotals,
SUM([media_est_cost] + [other_cost]) AS COSTTOTALS
FROM
[dbo].[dw_rpt_traffic]
WHERE
[create_dtg] >= ( Getdate() - 90 )
--GROUP BY CREATE_DTG
--ORDER BY CREATE_DTG ASC
I also tried using Parttion by, however, this returns the same value as the Revenuetotals.
Select a.dte, a.revenuetotals, a.COSTTOTALS, AVG(A.RevenueTotals) OVER (PARTITION BY a.dte ORDER BY a.dte ROWS 7 PRECEDING) as Day7Avg
from
(
select CAST(CREATE_DTG AS DATE) as dte,
SUM([AGENT_REV]+[ANCHOR_REV]+[CORP_REV]+[OFFSITE_REV]) as RevenueTotals,
SUM([MEDIA_EST_COST]+[OTHER_COST]) as COSTTOTALS
FROM [dbo].[dw_rpt_traffic]
where [CREATE_DTG] >= (GetDate() - 90)
GROUP BY CREATE_DTG
) as A
Group by a.dte, a.revenuetotals, a.COSTTOTALS
order by a.dte
Thanks, Karen

Answer 1

For rolling aggregates I typically use an OVER clause with ROWS [...] PRECEDING [...].
WITH cte
AS ( SELECT x.Date
,x.Revenue
,AVG(x.Revenue) OVER ( ORDER BY x.Date
ROWS BETWEEN 6 PRECEDING AND CURRENT ROW
) AS [MA7]
FROM ( SELECT CAST(t.Date AS DATE) AS [Date]
,SUM(t.Revenue) AS [Revenue]
FROM #tmp t
WHERE CAST(t.Date AS DATE) > CAST(GETDATE() - 96 AS DATE)
GROUP BY CAST(t.Date AS DATE)
) x
)
SELECT c.Date
,c.Revenue
,c.MA7
FROM cte c
WHERE c.Date > CAST(GETDATE() - 90 AS DATE)
ORDER BY c.Date;
The table above was generated with the following:
IF ( OBJECT_ID('tempdb..#tmp') IS NOT NULL )
DROP TABLE #tmp;
CREATE TABLE #tmp
(
[Date] DATETIME
,[Revenue] DECIMAL(18, 2)
);
--
DECLARE #first INT = 0
,#last INT = 200;
WHILE #first < #last
BEGIN
INSERT INTO #tmp
( Date, Revenue )
VALUES ( GETDATE() - #first * 0.5, RAND() * 100000 );
SET #first = #first + 1;
END;

Answer 2

Probably the easiest way uses outer apply:
with rt as (
select CAST(CREATE_DTG AS DATE) as dte,
SUM([AGENT_REV]+[ANCHOR_REV]+[CORP_REV]+[OFFSITE_REV]) as RevenueTotals,
SUM([MEDIA_EST_COST]+[OTHER_COST]) as COSTTOTALS
from [dbo].[dw_rpt_traffic]
where [CREATE_DTG] >= (GetDate() - 90)
)
select rt.*, rolling.avgrt
from rt outer apply
(select avg(rt2.RevenueTotals) as avgrt
from rt rt2
where rt2.dte >= dateadd(day, -6, rt.dte) and
rt2.dte <= rt.dte
) rolling
order by dte;