I've ran into a really stupid MySQL limitation today:
mysql> create table foo (foo_1 timestamp default now(), foo_2 timestamp default now());
ERROR 1293 (HY000): Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause
Nothing like that mentioned in the
docs, but there is a small (deadend) thread in the
lists.mysql.com -- nothing much
Meanwhile, on the other side of the town:
postgres=# create table foo (foo_1 timestamp default now(), foo_2 timestamp default now());
CREATE TABLE