QUERY TO GET REVERSE DUPLICATE

Create Table with Reverse Duplicate Data

CREATE TABLE GETREVERSEDUPLICATE
(COL1 VARCHAR(10),COL2 VARCHAR(10) ,COL3 INT)

INSERT INTO GETREVERSEDUPLICATE
SELECT 'A','B',10
UNION
SELECT 'C','D',20
UNION
SELECT 'B','A',10
UNION
SELECT 'D','C',20



SELECT * FROM GETREVERSEDUPLICATE
OUTPUT:
COL1 COL2 COL3
A B 10
B A 10
C D 20
D C 20

GET REVERSE DUPLICATE WITH EXPECTED OUTPUT
EXPECTED RESULT:
COL1 COL2 COL3
B A 10
D C 20



Query:
SELECT * FROM GETREVERSEDUPLICATE T
 WHERE Col1 > Col2
       AND EXISTS (
                   SELECT *
                     FROM GETREVERSEDUPLICATE  AS T1
                    WHERE T1.Col1 = T.Col2
                          AND T1.Col2 = T.Col1
                  );

OUTPUT:
COL1 COL2 COL3
B A 10
D C 20


Please try in Test environment only.