select AGE_CODE, count(STD.AGE_CODE) from SLEEP_TIME_DTL STD
group by AGE_CODE, STD.AGE_CODE;

select AGE_NAME 年齢階層, count(STD.TIME_CODE) from AGE_GRP AG
inner join SLEEP_TIME_DTL STL
on STL.AGE_CODE = AG.AGE_CODE

inner join SLEEP_TIME ST
on STD.TIME_CODE = ST.TIME_CODE

group by AG.AGE_CODE;