If I have the following scenario, would Replace be evaluated a single time?
DECLARE @text nvarchar(32) = 'This is a test field'
SELECT textField FROM Table
WHERE Id = @idICareAbout AND textField = REPLACE(@text, ' ', '')
I would hope that it would, but I tend to be nervous about it and do this instead:
DECLARE @text nvarchar(32)
Select @text = REPLACE('This is a test field', ' ', '')
SELECT textField FROM Table
WHERE Id = @idICareAbout AND textField = @text
Of course replace here is just an example, and I'm sure this second variant is probably clearer and safer, but occasionally when I'm over optimizing, I think "What if I didn't have to do the replace at all, because the first part of the WHERE expression evaluates to false". Normally this would be such a micro-optimization it's silly to even think about but there have been a few times where the scenario is such that it may make a not miniscule difference. (Many more where clause parameters and maybe a bunch of HASHBYTES of parameters passed in.)
So I'm just curious how SQL server handles it.
