mysql 如何拆分字符串数组

CREATE TABLE articles (
    id INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(255),
    tags VARCHAR(255)
);

INSERT INTO articles (title, tags) VALUES
('Article 1', 'tag1,tag2,tag3'),
('Article 2', 'tag2,tag4');

SELECT 
    a.id,
    a.title,
    SUBSTRING_INDEX(SUBSTRING_INDEX(a.tags, ',', numbers.n), ',', -1) AS tag
FROM 
    articles a
JOIN 
    (SELECT 1 n UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5) numbers
ON 
    CHAR_LENGTH(a.tags) - CHAR_LENGTH(REPLACE(a.tags, ',', '')) >= numbers.n - 1;

SELECT 
    a.id,
    a.title,
    REGEXP_SUBSTR(a.tags, '[^,]+', 1, levels.column_value) AS tag
FROM 
    articles a,
    lateral TABLE(GENERATE_series(1, LENGTH(a.tags) - LENGTH(REPLACE(a.tags, ',', '')) + 1)) levels(column_value);

SELECT 
    a.id,
    a.title,
    SUBSTRING_INDEX(SUBSTRING_INDEX(a.tags, ',', numbers.n), ',', -1) AS tag
FROM 
    articles a
JOIN 
    (SELECT 1 n UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5) numbers
ON 
    CHAR_LENGTH(a.tags) - CHAR_LENGTH(REPLACE(a.tags, ',', '')) >= numbers.n - 1
WHERE 
    SUBSTRING_INDEX(SUBSTRING_INDEX(a.tags, ',', numbers.n), ',', -1) <> '';