When using a SPT command like Insert into tableA Select * from tableB to add rows to a sql table, how do you deal with identity columns in one or both tables? Is the column_list required for one or both? If so, how do you keep the string length less than 255 characters? Concatenation seems to fail so there must be another way.

SQL Books Online indicates an identity column may be omitted from the columns_list in the INSERT command, but doesn't really give any details or examples (surprise!)