method 1:
create table t1(a int,b date);
insert into t1 values (1,sysdate);method 2:
create table t1(a int,b date default sysdate);
insert into t1(a) values (1);
create table t1(a int,b date);
insert into t1 values (1,sysdate);method 2:
create table t1(a int,b date default sysdate);
insert into t1(a) values (1);
新增表create table t1(a int,b date default sysdate);
修改表alter table t1 modify b default sysdate;