编辑代码

CREATE DATABASE test;
use test;
CREATE table R(
    SNO char(10),
    Sname char(10),
    st char(10)
);

create table R1(
    SNO char(10),
    Sname char(10),
    st char(5)
);



create table R2(
    SNO char(10) not null primary key,
    Sname char(10),
    st char(10)
);

insert into R(R.sno,R.Sname,R2.SNO,R2.Sname)
select sno,Sname
from R
left join R2 on R1.SNO=R.sno;