꿈라CBT다음 중 오류가 발생하는 SQL은?
보기
[TBL1]
| A |
|---|
| 100 |
| 200 |
| 300 |
[TBL2]
| A | B |
|---|---|
| 100 | 10 |
| 100 | 20 |
| 200 | NULL |
| 300 | 5 |
- 1
SELECT A FROM TBL1 WHERE A IN (SELECT A FROM TBL2);
- 2
SELECT A, (SELECT SUM(B) FROM TBL2 WHERE TBL1.A = TBL2.A) FROM TBL1;
- 3
SELECT A, (SELECT NVL(B, NULL) FROM TBL2 WHERE TBL1.A = TBL2.A) FROM TBL1;
- 4
SELECT A FROM TBL1 WHERE EXISTS (SELECT 1 FROM TBL2 WHERE TBL1.A = TBL2.A);