Complicated analytics issue... well, for me anyway

Question

Hi all.
For the sake of simplicity, I'll say I have a table that looks like this (simplified version of Kimball's employee monthly snapshot fact)
EMPLOYEE_TRANSACTION_KEY
LAST_DAY_OF_MONTH (date)
FISCAL_YEAR (4 digit year)
FISCAL_MONTH_NUM (1-12... our fiscal year runs Jul-Jun)
MONTH_ABBR (month abbreviation)
ACTIVE_COUNT (=1 if the employee transaction is "active" at the end of the month)
HIRED_COUNT (=1 if the employee transaction represents a "hire")
I need to create a crosstab report that shows month abbreviation on the left axis, fiscal year on the top axis, and for the data elements:
hires to date: running total of hires for the fiscal year (this is easy)
cumulative count: active count from last month of previous fiscal year + running total of hires
e.g. if at the end of FY06 (Jun 30) there were 5000 employees, then 100 hired in July, 50 hired in August, the August row should have "5150" as the cumulative count.
Yikes.
Thoughts?
-John

Answer 1

I've solved this to some extent (more below) using analytics.
First, I created a "Year End Active Count"calculation that = 1 if the row is from the last month of the fiscal year.
Next, I summed that value ("Current Year End Active Sum") using the analytic SUM function... so that every row in my report output has the year end active count in it.
Next, I created a calculation using LAG to pull the previous year's "Current Year End Active Sum"--actually, it pulls the value 12 rows before the current row--so that gives me the active count from the end of the previous fiscal year (or the start of the current fiscal year... depending on how you look at it) for each row in my report.
I can use that last piece along with my YTD Hires to get my desired calculation (Cumulative Active Headcount).
So yeah, I went crazy nuts with the analytic functions, and it more or less works.
I say "more or less" because the example I gave above was simplified. What I'm really trying to do is use Cumulative Active Heacount in ANOTHER calculation (YTD Terminations / Cumulative Active Count) ... and unless I include all of these functions in the worksheet output, I get an invalid identifier error when I run the report.
Any tips on resolving ORA-00904 invalid identifier issues would be welcome.
Thanks!
-John