SQL根據身份證統計年齡段

 Select sex,
 Sum(Case When 年齡 <=20 Then 1 Else 0 End) As '[0-20歲(人)]',
 Sum(Case When 年齡 Between 21 And 40 Then 1 Else 0 End) As '[21-40歲(人)]',
 Sum(Case When 年齡 Between 41 And 59 Then 1 Else 0 End) As '[41-59歲(人)]',
 Sum(Case When 年齡 Between 60 And 69 Then 1 Else 0 End) As '[60-69歲(人)]' ,
 Sum(Case When 年齡 Between 70 And 79 Then 1 Else 0 End) As '[70-79歲(人)]' ,
 Sum(Case When 年齡 Between 80 And 89 Then 1 Else 0 End) As '[80-89歲(人)]' ,
 Sum(Case When 年齡 >=90 Then 1 Else 0 End) As '[90歲以上(人)]'  
 From
 (
 select  *,FLOOR(DATEDIFF(DATE_FORMAT(now(),'%Y%m%d'),substring(identity,7,8))/365.25)  AS '年齡'  from user 
 ) s 
 WHERE sex!=''
 GROUP BY sex