Shulou(Shulou.com)06/01 Report--

SQL > create table t_test1 (id number,phone varchar2 (20) default null)

Table created.

SQL > CREATE SEQUENCE seq_test start with 1 increment by 1

SQL > select seq_test.nextval from dual

NEXTVAL 1

SQL > insert into t_test1 (phone) values ('1666')

1 row created.

SQL > select * from t_test1

2

ID PHONE 2 1666

SQL > alter table t_test1 add a2 varchar2 (20) default null

Table altered.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.