新建表B1create table Tbl_Customer(Customer Num(4)not null,Customer_Name varchar(10),Address varchar(20),City varchar(20),State varchar(20),Zip varchar(6),Referred Num(4)插入数据insert into tbl_customer values(1001,张三,白下区,南京,江苏,null )insert into tbl_customer values(1002,李四,徐汇区,上海,上海, null)insert into tbl_customer values(1003,王五,朝阳区,北京,北京,null)insert into tbl_customer values(1004,赵六,北大街,无锡,江苏, null)insert into tbl_customer values(1005,李三,平江路,
