举例：
SELECT (@i:=@i+1) AS PM,A.*,
U.TNAME,
U.ID_NUM,
U.ORG_NAME,
CASE WHEN U.SEXFLAG=1 THEN '男' WHEN U.SEXFLAG=2 THEN '女' ELSE '' END SEX,
CASE WHEN LENGTH(ID_NUM) = 18 THEN YEAR(NOW()) - CAST(SUBSTRING(ID_NUM, 7, 4) AS SIGNED) ELSE '' END AS AGE
FROM TB_GH_MARATHON A
LEFT JOIN TB_GH_USER U ON A.USER_ID = U.USER_ID
,(SELECT @i:=0) t
WHERE 1=1 AND A.STATE = '1'
加上红色字体的代码即可
