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CREATE TABLE table_name ( product, "GROUP", seq ) AS
SELECT 10, 5, 1 FROM DUAL UNION ALL
SELECT 10, 1, 5 FROM DUAL UNION ALL
SELECT 11, 2, 3 FROM DUAL UNION ALL
SELECT 11, 4, 4 FROM DUAL UNION ALL
SELECT 11, 24, 5 FROM DUAL
5 rows affected
MERGE INTO table_name dst
USING (
SELECT ROWID AS rid,
ROW_NUMBER() OVER (
PARTITION BY product
ORDER BY ROWNUM
) AS newSeq
FROM table_name
) src
ON ( dst.ROWID = src.rid )
WHEN MATCHED THEN
UPDATE SET seq = src.newSeq;
5 rows affected
SELECT * FROM table_name
| PRODUCT | GROUP | SEQ |
|---|---|---|
| 10 | 5 | 1 |
| 10 | 1 | 2 |
| 11 | 2 | 1 |
| 11 | 4 | 2 |
| 11 | 24 | 3 |