문서의 이전 판입니다!
| 물리명 | 논리명 | 타입 |
|---|---|---|
| 값없음 유형 | empty_type | 문자 |
| 빈 값/NULL | empty_value | 문자 |
CREATE TABLE ex_empty ( empty_type VARCHAR(100) NULL, empty_value VARCHAR(100) NULL );
INSERT INTO ex_empty (empty_type, empty_value) VALUES ('빈 값', '');
INSERT INTO ex_empty (empty_type, empty_value) VALUES ('NULL', NULL);
SELECT * FROM ex_empty WHERE empty_value IS NULL OR empty_value = '' ; SELECT * FROM ex_empty WHERE empty_value IS NOT NULL AND empty_value <> '' ;
SELECT * FROM ex_empty WHERE empty_value IS NULL OR empty_value = '' ; SELECT * FROM ex_empty WHERE empty_value IS NOT NULL AND empty_value <> '' ;
SELECT * FROM ex_empty WHERE empty_value IS NULL ; SELECT * FROM ex_empty WHERE empty_value IS NOT NULL ;
SELECT * FROM ex_empty WHERE empty_value IS NULL OR empty_value = '' ; SELECT * FROM ex_empty WHERE empty_value IS NOT NULL AND empty_value <> '' ;