mysql 将两列数据合并

CONCAT(column1, column2, ...)

SELECT CONCAT(first_name, ' ', last_name) AS full_name FROM users;

SELECT CONCAT(COALESCE(first_name, ''), ' ', COALESCE(last_name, '')) AS full_name FROM users;

-- 使用临时表
CREATE TEMPORARY TABLE temp_users AS
SELECT first_name, last_name FROM users;

SELECT CONCAT(first_name, ' ', last_name) AS full_name FROM temp_users;

-- 创建示例表
CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    first_name VARCHAR(50),
    last_name VARCHAR(50)
);

-- 插入示例数据
INSERT INTO users (first_name, last_name) VALUES
('John', 'Doe'),
(NULL, 'Smith'),
('Alice', NULL),
('Bob', 'Brown');

-- 查询并合并两列数据，处理空值
SELECT CONCAT(COALESCE(first_name, ''), ' ', COALESCE(last_name, '')) AS full_name FROM users;