Have a set of data. 750k records. Large number of fields. Only really need 2 fields and create a new calculated one.
I want to sum up those 750k to look like this: 1 record per dept, per month. I need to solve for Average of 12 prior months.
ie if the month is July 1, 2017, I need average of July 1 2016 - June 30 2017. One row per month as laid out in the table.
| Dept | Month | Average $$ Prior 12 month |
| Dept 1 | Jan 1 2017 | |
| Dept 2 | Jan 1 2017 | |
| Dept 3 | Jan 1 2017 | |
| Dept 4 | Jan 1 2017 | |
| Dept 5 | Jan 1 2017 | |
| Dept 1 | Feb 1 2017 | |
| Dept 2 | Feb 1 2017 | |
| Dept 3 | Feb 1 2017 | |
| Dept 4 | Feb 1 2017 | |
| Dept 5 | Feb 1 2017 | |
| Dept 1 | mm/dd/yyyy | |
| Dept 2 | mm/dd/yyyy | |
| Dept 3 | mm/dd/yyyy | |
| Dept 4 | mm/dd/yyyy | |
| Dept 5 | mm/dd/yyyy | |
So in my data: I have a dept, a date, a paid column.
I have a date column that is the first day of the month of the given date.
Don't believe it should be that hard. Thanks in advance.