Calculate YTD, Previous YTD in the same query - sql

Question

How could I calculate to calculate YTD and prior YTD in the same query?
I try to calculate weight and weight ytd. I didn't undestand how to add the calculation of prior ytd in the same query.
YTD: Sum Weight from the first of January to today
prior YTD: Sum
Weight from the first of January of last year to today minus 1 year
SELECT SUM(CASE
WHEN convert(date,s.Delivery_Year+'-'+ s.Delivery_month+'-'+ s.Delivery_day) BETWEEN dateadd(yy, DATEDIFF(yy, 0, GETDATE()), 0) AND GETDATE() THEN s.Weight
ELSE 0
END) AS WeightYTD ,
sum(Weight) AS weight ,
[Sales_Organization] ,
[Market_Grp] ,
[Delivery_Year] ,
[Delivery_month] ,
Delivery_day
FROM Fact_sales s
GROUP BY ,
[Sales_Organization] ,
[Market_Grp] ,
[Delivery_Year] ,
[Delivery_month] ,
Delivery_day

Answer 1

It's still quite unclear as to what results/behaviour you actually want.
One possible interpretation is that the "year to date" is relative to the date in the table, and not relative to "today" / GETDATE().
So...
for 14th March 2018 : YTD = 1st Jan 2018 to 14th March 2018
for 20th March 2019 : YTD = 1st Jan 2019 to 20th March 2019
That being the case, I would do the following to get the YTD column...
WITH
grouped_by_date AS
(
SELECT
[Sales_Organization],
[Market_Grp],
[Delivery_Year],
[Delivery_Month],
[Delivery_Day],
SUM([Weight]) AS Weight
FROM
Fact_sales s
GROUP BY
[Sales_Organization],
[Market_Grp],
[Delivery_Year],
[Delivery_Month],
[Delivery_Day]
),
cumulative_sum_for_ytd AS
(
SELECT
*,
SUM([Weight]) OVER (PARTITION BY [Delivery_Year]
ORDER BY [Delivery_Month], [Delivery_Day]
)
AS Weight_YTD
FROM
grouped_by_date
),
There isn't a LAG() function in SQL Server 2008, but there are "hacky tricks" that can simulate it...
hack_to_do_lag AS
(
SELECT
*,
CASE
WHEN [Delivery_Year]%2=1
THEN MAX(CASE WHEN [Delivery_Year]%2=0 THEN [Weight_YTD] END) OVER (PARTITION BY ([Delivery_Year]+0)/2)
ELSE MAX(CASE WHEN [Delivery_Year]%2=1 THEN [Weight_YTD] END) OVER (PARTITION BY ([Delivery_Year]+1)/2)
END
AS Weight_PreviousYTD
FROM
cumulative_sum_for_ytd
)
SELECT
*
FROM
hack_to_do_lag