I'm using SQL Server 2014. I have a Claims table containing totals of claims made per month in my system:
+-----------+-------------+------------+
| Claim_ID | Claim_Date | Nett_Total |
+-----------+-------------+------------+
| 1 | 31 Jan 2012 | 321454.67 |
| 2 | 29 Feb 2012 | 523542.34 |
| 3 | 31 Mar 2012 | 35344.33 |
| 4 | 30 Apr 2012 | 142355.63 |
| etc. | etc. | etc. |
+-----------+-------------+------------+
For a report I am writing I need to be able to produce a cumulative running total that resets to zero at the start of each fiscal year (in my country this is from March 1 to February 28/29 of the following year).
The report will look similar to the table, with an extra running total column, something like:
+-----------+-------------+------------+---------------+
| Claim_ID | Claim_Date | Nett_Total | Running Total |
+-----------+-------------+------------+---------------+
| 1 | 31 Jan 2012 | 321454.67 | 321454.67 |
| 2 | 29 Feb 2012 | 523542.34 | 844997.01 |
| 3 | 31 Mar 2012 | 35344.33 | 35344.33 | (restart at 0
| 4 | 30 Apr 2012 | 142355.63 | 177699.96 | for new yr)
| etc. | etc. | etc. | |
+-----------+-------------+------------+---------------+
I know windowing functions are very powerful and I've used them in rudimentary ways in the past to get overall sums and averages while avoiding needing to group my resultset rows. I have an intuition that I will need to employ the 'preceding' keyword to get the running total for the current fiscal year each row falls into, but I can't quite grasp how to express the fiscal year as a concept to use in the 'preceding' clause (or if indeed it's possible to use a date range in this way).
Any assistance on the way of "phrasing" the fiscal year for the "preceding" clause will be of enormous help to me, please.