CREATE TABLE TestTable1 (
  id NUMBER(10),
  field1 NUMBER(5),
  field3 VARCHAR2(40),
  self_ref NUMBER(10),

  CONSTRAINT TestTable1_pk PRIMARY KEY (id),
  CONSTRAINT TestTable1_self_ref_fk foreign KEY (self_ref)
    references TestTable1(id)
);

CREATE TABLE TestTable2 (
  field1 NUMBER(5),
  field2 VARCHAR2(30),
  field3 NUMBER
);

-- column ambiguously defined
SELECT field3 FROM TestTable1 left join TestTable2 ON TestTable1.field1 = TestTable2.field1;

-- column ambiguously defined
SELECT field3
  FROM TestTable1
    left join TestTable1 TestTable1_2 ON TestTable1.self_ref = TestTable1_2.id;

-- exception gone away
SELECT field3
  FROM TestTable1
    join TestTable2 ON TestTable1.field1 = TestTable2.field1
    left join TestTable1 TestTable1_2 ON TestTable1.self_ref = TestTable1_2.id;