Do you know what the problem is?
I use Where Not Exists all the time, typically when I’m incremental loading. (a detailed video of how to do that can be found here)
Problem is, it doesn’t work as (at least I’d) imagine it would. In my mind Where Not Exists is the opposite of Where Exists although it isn’t!! That’s really important to know to stop you loosing any data.
In this video I will show you in detail how it works:
Note: I’ve recorded the videos in highest resolution possible. So please view them in 1080 or 720P (HD) for best quality. Cheers!