create table table1(id int,name varchar(10))
create table table2(id int,score int)
insert into table1 values( 1,'lee') ;
insert into table1 values(2,'zhang') ;
insert into table1 values(4,'wang') ;
insert into table2 values(1,90) ;
insert into table2 values(2,100) ;
insert into table2 values(3,70) ;
select * from table1
select * from table2
select * from table1 left join table2 on table1.id=table2.id
select * from table1 right join table2 on table1.id=table2.id
select * from table1 inner join table2 on table1.id=table2.id