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CREATE TABLE QEEN (ID INT, A INT, B INT); INSERT INTO QEEN VALUES (1, 22, 32), (2, 22, 55), (3, 32, 22), (4, 32, 77); SELECT * FROM QEEN WHERE NOT EXISTS ( SELECT ID FROM QEEN REVERSE_QEEN WHERE REVERSE_QEEN.A = QEEN.B AND REVERSE_QEEN.B = QEEN.A ); SELECT QEEN.* FROM QEEN LEFT JOIN QEEN REVERSE_QEEN ON REVERSE_QEEN.A = QEEN.B AND REVERSE_QEEN.B = QEEN.A WHERE REVERSE_QEEN.ID IS NULL; WITH ALL_QEEN AS ( SELECT ID, A, B FROM QEEN UNION ALL SELECT ID, B, A FROM QEEN ) SELECT * FROM ALL_QEEN