mysql 定义数组变量

SET @json_array = '[1, 2, 3, 4, 5]';

SELECT @json_array;

-- 获取数组长度
SELECT JSON_LENGTH(@json_array);

-- 获取数组中的元素
SELECT JSON_EXTRACT(@json_array, '$[2]');

-- 添加元素到数组
SET @json_array = JSON_ARRAY_APPEND(@json_array, '$', 6);
SELECT @json_array;

SET @string_array = '1,2,3,4,5';

SELECT @string_array;

SELECT SUBSTRING_INDEX(SUBSTRING_INDEX(@string_array, ',', numbers.n), ',', -1) AS val
FROM (SELECT 1 n UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9 UNION ALL SELECT 10) numbers
WHERE numbers.n <= LENGTH(@string_array) - LENGTH(REPLACE(@string_array, ',', '')) + 1;

CREATE TEMPORARY TABLE temp_array (
    id INT AUTO_INCREMENT PRIMARY KEY,
    value INT
);

INSERT INTO temp_array (value) VALUES (1), (2), (3), (4), (5);

SELECT * FROM temp_array;