mysql根据身份证号码查询出几零后分布

select name,count(1)from (
select birthday,(case when birthday  between '1940' and '1949' then '40后' 
when birthday  between '1950' and '1959' then '50后' 
when birthday  between '1960' and '1969' then '60后' 
when birthday  between '1970' and '1979' then '70后' 
when birthday  between '1980' and '1989' then '80后' 
when birthday  between '1990' and '1999' then '90后' 
else '00后' 
 end) name from ( 
select SUBSTRING(id_number,7,4) AS birthday from v_app_queue_sq
where 
id_number<>'' AND id_number IS NOT NULL AND  LENGTH(id_number)=18
) m) b group by name