I just had a SSIS package that had been running every day for the last couple of years without any problems, which failed on me with the following error message:
Warning: Null value is eliminated by an aggregate or other SET operation
The SQL source had a group by, where I was taking a minimum on some datetime fields. I needed it to return NULL values because I had some additional logic that took these NULL values into account.
What was even stranger was, that when I ran the package by double clicking it on the server, it completed with success.
So apparently a warning from the SQL server causes an error in SSIS, but only sometimes….. Nice….
The solution is to either change your SQL, so you don’t get NULL values, by for instance use COALESCE or ISNULL, or if you can’t do that, put this statement in front of your SQL : SET ANSI_WARNINGS OFF
Read more about the problem/bug here: