Invalid use of side-effecting or time-dependent operator in 'UPDATE' within a function.

I have run into a very interesting and very frustrating problem with Sql Server.

So far my experimenting points to a bug in sql server, though I wish it was something I was doing wrong.

I have created a scalar-valued function that uses a table variable. According to microsoft's msdn and several other sites doing inserts, updates, and deletes on local table variables in user functions is very valid.

In my case I was able to get Inserts and Deletes to work, but am having all sorts of issues with the Update statement. I copied microsofts example one and that executed fine, so then I started replacing pieces of their code with my own and saving/executing until it was a duplicate of my original function. At this point I assumed something must have been cached incorrectly in my original query window.

However, I needed to add a second update statement to the function and while the first one still works the second one won't take. So after messing with it for a bit I once again executed the microsoft example and bit by bit copied each piece of my sproc over replacing their code; and what do you know it worked again.

The only difference I can see is that their update statements are inside of a While loop, so it is still a bug in sql server, but I might be getting a little closer to a better work around.

Update: Looks like it might have been my problem after all, which is wonderful. I was using square brackets around my table variables; on a co-workers suggestion I removed those and my queries started working.

I'm guessing that all I was doing before was figuring out a way to bypass the query parser as can often happen in large stored procedures.