Comment by abtinf

Aerospace. I was interacting with data sets on the order of hundreds of millions to low billions of rows. This particular company had legacy WinForms applications running against SQL Server. Excel can directly connect to the db to run complex, multi-step queries (IIRC it holds the connection open so you can do things in temp table). Hitting “Refresh” in Excel can trigger a lot of work. And then it can do a ton of processing locally. IIRC, there were no row limits on what excel could process locally (so long as the final result stayed under the sheet limit).