mysql 获取拼音首字母

DELIMITER $$

CREATE FUNCTION GetPinyinInitial(str VARCHAR(255)) RETURNS VARCHAR(255)
DETERMINISTIC
BEGIN
    DECLARE result VARCHAR(255) DEFAULT '';
    DECLARE i INT DEFAULT 1;
    DECLARE len INT DEFAULT LENGTH(str);
    DECLARE temp CHAR(1);

    WHILE i <= len DO
        SET temp = SUBSTRING(str, i, 1);
        CASE temp
            WHEN '爱' THEN SET result = CONCAT(result, 'A');
            WHEN '安' THEN SET result = CONCAT(result, 'A');
            -- 其他汉字的拼音首字母映射
            ELSE SET result = CONCAT(result, temp);
        END CASE;
        SET i = i + 1;
    END WHILE;

    RETURN result;
END$$

DELIMITER ;

SELECT GetPinyinInitial('你好') AS pinyin_initial;