Can you use a cross data base join? Or maybe create a master file with ALL the incident dates and use this as your primary data source for blending.
Cross DB join won't allow full outer. I'll try creating a master table and try to use it as a join source. Although I'm trying to avoid any external ETLs or another table to keep up to date, but if there is no other way, it might be the solution.
I'll report back if it works.
UPDATE: Is not working. Employee ID is part of the key, and since I'm joining both tables with the master date table, and I don't have the ID on that one, is mixing everyone and it will be impossible to count records from one table or the other. The solution will be a union, but looks like building a 3rd table with an ETL engine that can union those together is the only viable solution.
The problem with that is that I don't want to duplicate the data on a 3rd table, and I don't want to have to keep an eye on it, running the ETL on a regular basis to keep it updated, etc. Is an administrative nightmare.
Can't believe there is no other way.