mysql 拆分多个逗号

CREATE TABLE users (
    id INT PRIMARY KEY,
    name VARCHAR(100),
    hobbies VARCHAR(255)
);

INSERT INTO users (id, name, hobbies) VALUES
(1, 'Alice', 'reading,swimming'),
(2, 'Bob', 'gaming,cooking');

SELECT 
    id, 
    name, 
    SUBSTRING_INDEX(SUBSTRING_INDEX(hobbies, ',', numbers.n), ',', -1) AS hobby
FROM 
    (SELECT 1 n UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5) numbers INNER JOIN users
ON CHAR_LENGTH(hobbies) - CHAR_LENGTH(REPLACE(hobbies, ',', '')) >= numbers.n - 1;

CREATE TEMPORARY TABLE temp_hobbies (
    id INT,
    hobby VARCHAR(255)
);

DELIMITER $$
CREATE PROCEDURE SplitHobbies()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE v_id INT;
    DECLARE v_hobby VARCHAR(255);
    DECLARE cur CURSOR FOR SELECT id, SUBSTRING_INDEX(SUBSTRING_INDEX(hobbies, ',', numbers.n), ',', -1) AS hobby
    FROM (SELECT 1 n UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5) numbers INNER JOIN users
    ON CHAR_LENGTH(hobbies) - CHAR_LENGTH(REPLACE(hobbies, ',', '')) >= numbers.n - 1;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN cur;

    read_loop: LOOP
        FETCH cur INTO v_id, v_hobby;
        IF done THEN
            LEAVE read_loop;
        END IF;
        INSERT INTO temp_hobbies (id, hobby) VALUES (v_id, v_hobby);
    END LOOP;

    CLOSE cur;
END$$
DELIMITER ;

CALL SplitHobbies();

SELECT * FROM temp_hobbies;

UPDATE users SET hobbies = REPLACE(hobbies, ',,', ',');