But with select into you cannot have an identity column , you have to use row_number otherwise , which may affect the performance when you are dealing with large number of rows.
1. That is incorect:
select identity(int, 1,1) as qq,* into #tbl from master..sysdatabases
2. That doesn't change the fact that there is no difference between the temp table regardless of how you create them.
Don't just give the hungry man a fish, teach him how to catch it as well.