Según la documentación en timestamp y datetime escriba columnas:
Otros ejemplos :
mysql> create table tbl_so_q23671222_1( ts timestamp(3) default now() );
ERROR 1067 (42000): Invalid default value for 'ts'
mysql> create table tbl_so_q23671222_1( ts timestamp(3) default now(3) );
Query OK, 0 rows affected (0.59 sec)
mysql> create table tbl_so_q23671222_2( ts timestamp(3) default current_timestamp );
ERROR 1067 (42000): Invalid default value for 'ts'
mysql> create table tbl_so_q23671222_2( ts timestamp(3) default current_timestamp(3) );
Query OK, 0 rows affected (0.38 sec)
mysql> desc tbl_so_q23671222_1;
+-------+--------------+------+-----+----------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+----------------------+-------+
| ts | timestamp(3) | NO | | CURRENT_TIMESTAMP(3) | |
+-------+--------------+------+-----+----------------------+-------+
1 row in set (0.01 sec)
mysql> desc tbl_so_q23671222_2;
+-------+--------------+------+-----+----------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------------+------+-----+----------------------+-------+
| ts | timestamp(3) | NO | | CURRENT_TIMESTAMP(3) | |
+-------+--------------+------+-----+----------------------+-------+
1 row in set (0.01 sec)
Referirse a :
Inicialización y Actualización para TIMESTAMP y DATETIME
