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CREATE TABLE MR_PATIENT_IDS AS SELECT 1 AS patient_no, 1 AS id_no FROM DUAL UNION ALL SELECT 2 AS patient_no, 1 AS id_no FROM DUAL UNION ALL SELECT 2 AS patient_no, 2 AS id_no FROM DUAL UNION ALL SELECT 3 AS patient_no, 3 AS id_no FROM DUAL UNION ALL SELECT 3 AS patient_no, 4 AS id_no FROM DUAL UNION ALL SELECT 4 AS patient_no, 4 AS id_no FROM DUAL UNION ALL SELECT 5 AS patient_no, 4 AS id_no FROM DUAL;
7 rows affected
SELECT t1.patient_no, t1.id_no FROM MR_PATIENT_IDS t1 INNER JOIN ( SELECT id_no, COUNT(*) AS count FROM MR_PATIENT_IDS GROUP BY id_no HAVING COUNT(*) > 1 ) t2 ON t1.id_no = t2.id_no
PATIENT_NO
ID_NO
1
1
2
1
3
4
4
4
5
4