Performance Difference in comparing integers and comparing strings

Question

Can anyone provide any concrete evidence of performance when comparing

int = int

and:

string = string

in

Answer 1

As Steve pointed out in the comments, the presence and constitution of indexes will greatly impact your results; however, since SQL Server works with pages to lookup data, and narrower column types can store more data per page, using a narrow type can perform better than a wider type where there are more values to consider.

So, if you have a small table (few rows), it probably doesn't matter; big table? Put an index on the int column and it will probably out-perform an indexed varchar column.

Of course, what constitutes large or small tables depends on your hardware.