You can add a where clause. If it is all positive integers (i.e., you want to look for only digits 0 through 9), then you can do this:
SUBSTRING(Name,5,3) NOT LIKE '%[^0-9]%'Or if you have negative numbers also use '%[^0-9-]%', decimal points, then'%[^0-9-.]%' etc.
Another way is to use the isnumeric function.
ISNUMERIC(SUBSTRING(Name,5,3)) = 1