insert into mytable (column1, column 2, column3)
Select thiscolumn, '1', now()
From anotherTable;
insert into mytable (column1, column 2, column3)
(Select thiscolumn
From anotherTable, '1', now());
will not work in any dbms.
insert into mytable (column1, column 2, column3)
values ((Select thiscolumn
From anotherTable), '1', now());
may work in some.