SELECT 'A' T1_COL1 FROM DUAL UNION ALL
SELECT 'B' T1_COL1 FROM DUAL UNION ALL
SELECT 'B' T1_COL1 FROM DUAL UNION ALL
SELECT 'C' T1_COL1 FROM DUAL
2번 테이블
SELECT 'A' T2_COL1 FROM DUAL UNION ALL
SELECT 'B' T2_COL1 FROM DUAL UNION ALL
SELECT 'B' T2_COL1 FROM DUAL UNION ALL
SELECT 'B' T2_COL1 FROM DUAL UNION ALL
SELECT 'D' T2_COL1 FROM DUAL
1번 테이블과 2번테이블 INNER-JOIN
SELECT T1.T1_COL1, T2.T2_COL1
FROM ( SELECT 'A' T1_COL1 FROM DUAL UNION ALL
SELECT 'B' T1_COL1 FROM DUAL UNION ALL
SELECT 'B' T1_COL1 FROM DUAL UNION ALL
SELECT 'C' T1_COL1 FROM DUAL ) T1,
( SELECT 'A' T2_COL1 FROM DUAL UNION ALL
SELECT 'B' T2_COL1 FROM DUAL UNION ALL
SELECT 'B' T2_COL1 FROM DUAL UNION ALL
SELECT 'B' T2_COL1 FROM DUAL UNION ALL
SELECT 'D' T2_COL1 FROM DUAL ) T2
WHERE T1.T1_COL1 = T2.T2_COL1