mysql 中英文混合提取首字母函数

-- 提取首字母函数定义
DELIMITER $$
CREATE FUNCTION `INITIALS`(P_NAME VARCHAR(255)) RETURNS varchar(255) CHARSET utf8
DETERMINISTIC
BEGIN
DECLARE V_RETURN VARCHAR(255);
DECLARE V_BOOL INT DEFAULT 0;
DECLARE FIRST_VARCHAR VARCHAR(1);

SET FIRST_VARCHAR = left(CONVERT(P_NAME USING gbk),1);
SELECT FIRST_VARCHAR REGEXP ‘[a-zA-Z]‘ INTO V_BOOL;
IF V_BOOL = 1 THEN
SET V_RETURN = FIRST_VARCHAR;
ELSE
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‘);
END IF;
RETURN V_RETURN;
END$$
DELIMITER;

SELECT
            b.brand_id,
            b.brand_code,
            b.brand_name,
            INITIALS(b.brand_name) as INITIALS,   -- 用于提取首字母 // 排序 
            b.brand_remark,
            b.brand_logo_url,
            b.brand_banner_url,
            b.id
        FROM
            t_brand_shop_extend b
        order by INITIALS  asc