MySQL获取汉字的拼音首字母

DELIMITER $$
CREATE FUNCTION `pinyin`(P_NAME VARCHAR(255)) RETURNS varchar(255) CHARSET utf8
DETERMINISTIC
BEGIN
    DECLARE V_COMPARE VARCHAR(255);
    DECLARE V_RETURN VARCHAR(255);
    DECLARE I INT;
    SET I = 1;
    SET V_RETURN = '';
    #循环截取字符
    while I < LENGTH(P_NAME) do
        SET V_COMPARE = SUBSTR(P_NAME, I, 1);
        IF (V_COMPARE != '') THEN
            #字符串拼接
            SET V_RETURN = CONCAT(V_RETURN, to_frist_pinyin(V_COMPARE));
        END IF;
        SET I = I + 1;
    end while;
    IF (ISNULL(V_RETURN) or V_RETURN = '') THEN
        SET V_RETURN = P_NAME;
    END IF;
    RETURN V_RETURN;
END$$
 
 
 
CREATE FUNCTION `to_frist_pinyin`(P_NAME VARCHAR(255)) RETURNS varchar(255) CHARSET utf8
BEGIN
    DECLARE V_RETURN VARCHAR(255);
    DECLARE V_FIRST_CHAR VARCHAR(255);
    #这块主要意思是假如传入的是英文串的话，只取首字母
    set V_FIRST_CHAR =UPPER(LEFT(CONVERT(P_NAME USING gbk),1));
    set V_RETURN = V_FIRST_CHAR;
#如果是这些特殊符号，直接返回#   
IF V_FIRST_CHAR in ('（','）','《','》')
THEN SET V_RETURN = '';
#两个不相等只有一个情况，V_FIRST_CHAR是中文汉字或者中文符号。
elseif LENGTH( V_FIRST_CHAR) <> CHARACTER_LENGTH( V_FIRST_CHAR )
            then   
                SET V_RETURN = ELT(INTERVAL(CONV(HEX(left(CONVERT(P_NAME USING gbk),1)),16,10),
                    0xB0A1,0xB0C5,0xB2C1,0xB4EE,0xB6EA,0xB7A2,0xB8C1,0xB9FE,0xBBF7,
                    0xBFA6,0xC0AC,0xC2E8,0xC4C3,0xC5B6,0xC5BE,0xC6DA,0xC8BB,
                    0xC8F6,0xCBFA,0xCDDA,0xCEF4,0xD1B9,0xD4D1),   
                    'A','B','C','D','E','F','G','H','J','K','L','M','N','O','P','Q','R','S','T','W','X','Y','Z');
#如果是下面的直接原样输出                  
elseif V_FIRST_CHAR in ('A','B','C','D','E','F','G','H','J','K','L','M','N','O','P','Q','R','S','T','W','X','Y','Z',
                                                '1','2','3','4','5','6','7','8','9','0','*','+','-','=','/','\\','{','}','[',']','(',')','（','）')
            then SET V_RETURN = V_RETURN;
#其他的输出#            
else
            SET V_RETURN = '#';
END IF;
        #为空的话输出#
        RETURN IFNULL(V_RETURN,'#');
END$$
DELIMITER ;