mysql数组分割字符串函数

SELECT SUBSTRING_INDEX('apple,banana,orange', ',', 1); -- 返回 'apple'
SELECT SUBSTRING_INDEX('apple,banana,orange', ',', -1); -- 返回 'orange'

SELECT FIND_IN_SET('banana', 'apple,banana,orange'); -- 返回 2
SELECT IF(FIND_IN_SET('grape', 'apple,banana,orange'), 'Found', 'Not Found'); -- 返回 'Not Found'

DELIMITER //

CREATE FUNCTION SPLIT_STR(
    x VARCHAR(255),
    delim VARCHAR(12),
    pos INT
)
RETURNS VARCHAR(255)
DETERMINISTIC
BEGIN
    RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(x, delim, pos),
           LENGTH(SUBSTRING_INDEX(x, delim, pos - 1)) + 1),
           delim, '');
END//

DELIMITER ;

SELECT SPLIT_STR('apple,banana,orange', ',', 2); -- 返回 'banana'