Merged cells? Very unclear what you're asking here, as the picture is of your Group properties, not the dataset.

No, T-SQL doesn't permit the OVER clause to be defined anywhere else other than in the expression that requires it. That will mean repeating it, if you have multiple columns...

It seems like you're looking for a reason, rather than having one. Based on the little detail we have, it seems there's little reason why you wouldn't add the index.

Does the index have a significant improvement? If it does, what reasons do you have to not add it? Why do you beleive that the report will never have any...

Only just noticed this, but for those that still have 2012 instances and use SSDT, be careful about updating your version. I just noticed that V15.8.1 removes support for SQL...

For SQL Server 2008 you'll needs BIDS on VS2008 (which, if i recall correctly is on the installation media for SQL Server 2008(R2)). For SQL Server 2016, you can use...

I agree with Phil here, I don't see anything wrong with your query. You can compare columns regardless of their names and datatypes (just that with the latter implicit conversions...

If you want to find out where the data is coming from then best thing to do would be to open the SSIS Project in the relevant version of SSDT....

That's very open to injection as well, you should be using QUOTENAME, not wrapping the object names with brackets ([]); the latter can easily be got around. I'd recommend using...

Looks like that...