联合查询怎么搞，刚刚学习

联合查询怎么搞，新人小白一脸迷茫，求大神帮帮我！

1.select t1.,t2. from table_test1 t1 left join talbe_test2 t2 on t1.id=t2.id
2.select t1.,t2. from table_test1 t1 right join talbe_test2 t2 on t1.id=t2.id