法一：

Sql代码  收藏代码

CREATE TABLE customers

(

  customerid SERIAL primary key ,

  companyname character varying,

  contactname character varying,

  phone character varying,

  country character varying

)

 法二：

Sql代码  收藏代码

CREATE SEQUENCE event_id_seq

START WITH 1

INCREMENT BY 1

NO MINVALUE

NO MAXVALUE

CACHE 1;  

alter table event alter column id set default nextval('event_id_seq');