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create table t1
( id int not null,
planet varchar(20) not null
) ;
insert into t1 (id, planet) values (1, 'jupiter');
1 rows affected
insert into t1 (id, planet) values (2, 'earth');
1 rows affected
create table t2
( id int not null,
planet varchar(20) not null
) ;
insert into t2 (id, planet) values (1, 'jupiter');
1 rows affected
insert into t2 (id, planet) values (2, 'earth');
1 rows affected
SELECT * FROM t1 NATURAL JOIN t1;
| ID | PLANET |
|---|---|
| 1 | jupiter |
| 1 | jupiter |
| 2 | earth |
| 2 | earth |
SELECT id, planet FROM t1 NATURAL JOIN t1 t2;
| ID | PLANET |
|---|---|
| 1 | jupiter |
| 2 | earth |
SELECT * FROM t1 NATURAL JOIN t2;
| ID | PLANET |
|---|---|
| 1 | jupiter |
| 2 | earth |
SELECT id, planet FROM t1, t1;
ORA-00918: column ambiguously defined
SELECT id, planet FROM t1, t2 t1;
ORA-00918: column ambiguously defined