ChrisM@Work (10/8/2012)
That's unlikely. If a column has a not null constraint, it won't allow nulls.A shotgun approach like this puts shivers down my spine. You have a legacy app which uses NULL, empty string and a single space, all of which mean different things and on which the app and the database probably rely for data integrity and functionality, and you want to change all of these values to support a few reports. I'd recommend you perform a great deal more testing before proceeding with this. Find out exactly why the reports are giving unexpected results - track down the tables and columns used by them and assess the impact on other processes of the changes which you would make to those tables and columns. If you're going to make any changes then do it in a test environment.
And you can't ALTER a column to NOT NULL if it contains NULL values already.
My take on the last part is that it's more likely sloppiness on the part of the developers that let NULL, '' and ' ' into the column. Maybe they mean different things but probably they don't.
But I agree with the need to test whatever you end up doing.
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St