INSERT INTO TABLE1 (col 1, col2,..., the_extra_col) SELECT *, NULL from TABLE2
ou
INSERT INTO TABLE1 (col 1, col2,..., the_extra_col) SELECT *, the_default_date_here from TABLE2
INSERT INTO TABLE1 (col 1, col2,..., the_extra_col) SELECT *, NULL from TABLE2
ou
INSERT INTO TABLE1 (col 1, col2,..., the_extra_col) SELECT *, the_default_date_here from TABLE2