SQL取字段中首字母，并按首字母排序

SELECT
	ID, USER_NAME userName,contacts, province, email, 
	lower(case when contacts REGEXP '^[a-zA-Z]' then LEFT(contacts, 1)
		when contacts REGEXP '^[0-9]' then LEFT(contacts, 1)
		else ELT(INTERVAL(CONV(HEX(LEFT(CONVERT(contacts 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) firstChar
from osmcs_user 
order by firstChar asc, contacts asc