mysql 生成唯一随机数

CREATE TABLE example (
    id CHAR(36) PRIMARY KEY,
    name VARCHAR(255)
);

INSERT INTO example (id, name) VALUES (UUID(), 'John Doe');

CREATE TABLE example (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(255)
);

INSERT INTO example (name) VALUES ('John Doe');

UPDATE example SET id = FLOOR(RAND() * 1000000) WHERE id IS NULL;

DELIMITER //

CREATE PROCEDURE generate_unique_random_number(IN table_name VARCHAR(255), IN column_name VARCHAR(255))
BEGIN
    DECLARE random_number INT;
    DECLARE is_unique BOOLEAN DEFAULT FALSE;

    WHILE NOT is_unique DO
        SET random_number = FLOOR(RAND() * 1000000);
        SET @sql = CONCAT('SELECT COUNT(*) INTO @count FROM ', table_name, ' WHERE ', column_name, ' = ', random_number);
        PREPARE stmt FROM @sql;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;

        IF @count = 0 THEN
            SET is_unique = TRUE;
            SET @sql = CONCAT('UPDATE ', table_name, ' SET ', column_name, ' = ', random_number, ' WHERE id IS NULL');
            PREPARE stmt FROM @sql;
            EXECUTE stmt;
            DEALLOCATE PREPARE stmt;
        END IF;
    END WHILE;
END //

DELIMITER ;