Konfiguracja schematu Oracle 11g R2 :
CREATE TABLE test (col1, col2, col3, col4, col5 ) AS
SELECT 1, 'A', 'B', 'C', 'D' FROM DUAL
UNION ALL SELECT 2, 'A', 'B', 'C', NULL FROM DUAL
UNION ALL SELECT 3, 'C', 'A', NULL, NULL FROM DUAL
UNION ALL SELECT 4, 'D', 'A', 'C', NULL FROM DUAL
UNION ALL SELECT 5, NULL, NULL, NULL, NULL FROM DUAL
UNION ALL SELECT 6, NULL, NULL, NULL, 'A' FROM DUAL
UNION ALL SELECT 7, 'B', NULL, NULL, 'A' FROM DUAL
UNION ALL SELECT 8, NULL, 'C', NULL, 'A' FROM DUAL;
Zapytanie 1 :
Jeśli nie ma NULL wartości między innymi wartościami (wprowadzi wiele przecinków w wierszach 7 i 8):
SELECT col1,
TRIM( ',' FROM col2||','||col3||','||col4||','||col5 ) AS col2
FROM test
Wyniki :
| COL1 | COL2 |
|------|---------|
| 1 | A,B,C,D |
| 2 | A,B,C |
| 3 | C,A |
| 4 | D,A,C |
| 5 | (null) |
| 6 | A |
| 7 | B,,,A |
| 8 | C,,A |
Ostatnie dwa zapytania będą działać dla wszystkich przykładów:
Zapytanie 2 :
SELECT col1,
TRIM( ',' FROM col2 || NVL2( col3, ','||col3, NULL ) || NVL2( col4, ','||col4, NULL ) || NVL2( col5, ','||col5, NULL ) ) AS col2
FROM test
Wyniki :
| COL1 | COL2 |
|------|---------|
| 1 | A,B,C,D |
| 2 | A,B,C |
| 3 | C,A |
| 4 | D,A,C |
| 5 | (null) |
| 6 | A |
| 7 | B,A |
| 8 | C,A |
Zapytanie 3 :
SELECT col1,
REGEXP_REPLACE( col2||','||col3||','||col4||','||col5, '(^|,),+|,+($)', '\1' ) AS col2
FROM test
Wyniki :
| COL1 | COL2 |
|------|---------|
| 1 | A,B,C,D |
| 2 | A,B,C |
| 3 | C,A, |
| 4 | D,A,C |
| 5 | (null) |
| 6 | A |
| 7 | B,A |
| 8 | C,A |
