内连接

teledb=# select * from teledb_pg inner join teledb_pg1 on teledb_pg.id = teledb_pg1.id;
 id | nickname | id | nickname 
----+----------+----+----------
  3 | pg       |  3 | pg
(1 row)

左外连接

teledb=# select * from teledb_pg left join teledb_pg1 on teledb_pg.id = teledb_pg1.id;
 id |  nickname  | id | nickname 
----+------------+----+----------
  1 | teledb    |    | 
  1 | hello,pgxc |    | 
  2 | TELEDB    |    | 
  3 | pg         |  3 | pg
  4 |            |    | 
(5 rows)

右外连接

teledb=# select * from teledb_pg right join teledb_pg1 on teledb_pg.id = teledb_pg1.id;
 id | nickname | id | nickname 
----+----------+----+----------
    |          |  5 | test
  3 | pg       |  3 | pg
(2 rows)

全连接

teledb=# select * from teledb_pg full join teledb_pg1 on teledb_pg.id = teledb_pg1.id;
 id |  nickname  | id | nickname 
----+------------+----+----------
  1 | teledb    |    | 
  3 | pg         |  3 | pg
  4 |            |    | 
  1 | hello,pgxc |    | 
  2 | TELEDB    |    | 
    |            |  5 | test
(6 rows)