For display purposes these 2 results would be identical (except of course for the specific words):
SELECT 'THIS IS A VARCHAR STRING', N'THIS IS AN NVARCHAR STRING';
There may be a slight performance boost in a case where you do an assignment to a type VARCHAR variable or column, like:
DECLARE @MyString NVARCHAR(100);
SELECT @MyString = N'THIS IS AN NVARCHAR STRING';
Because if you omit the N' annotation, SQL would need to do an implicit conversion to the NVARCHAR type. So the annotation simply defines the string that follows as Unicode string.
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]
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