选择第0行(C2)的Oracle值在C3中为空，所有其他行(C2)的值为NULL -Oracle

CREATE TABLE my_table (
    id NUMBER,
    C2 VARCHAR2(50),
    C3 VARCHAR2(50)
);

SELECT * FROM my_table;

SELECT id, C2, C3
FROM my_table
WHERE (C2 IS NULL AND C3 IS NULL) OR (C2 IS NOT NULL AND C3 = '');

SELECT id, C2, C3
FROM my_table
WHERE (C2 IS NULL AND COALESCE(C3, '') = '') OR (C2 IS NOT NULL AND C3 IS NULL);

-- 创建示例表
CREATE TABLE my_table (
    id NUMBER,
    C2 VARCHAR2(50),
    C3 VARCHAR2(50)
);

-- 插入示例数据
INSERT INTO my_table (id, C2, C3) VALUES (0, 'value1', '');
INSERT INTO my_table (id, C2, C3) VALUES (1, NULL, NULL);
INSERT INTO my_table (id, C2, C3) VALUES (2, 'value2', 'value2');

-- 查询语句
SELECT id, C2, C3
FROM my_table
WHERE (C2 IS NULL AND COALESCE(C3, '') = '') OR (C2 IS NOT NULL AND C3 IS NULL);