A.
select min(sbirthday)'最早出生,max(sbirthsday)'最早出生',datediff(day,min(sbirthday),max(sbirthday)) from t_student
B.
select min(sbirthday)'最晚出生',max(sbirthday)'最早出生',datediff(day,max(sbirthday),min(sbirthday)) from t_student
C.
select min(sbirthday)'最早出生',max(sbirthday)'最晚出生',max(sbirthday)-min(sbirthday) from t_student