Hi people, i am trying to get this done:

select e.lname
from employee e, department d
where e.ssn = d.essn and months_between(sysdate,e.bdate) <= all(select months_between(sysdate,e2.bdate)
from employee e2,department d2
where e2.ssn = d2.mgrssn);

and this is the error it gives me:
4* where e2.ssn = d2.mgrssn)
where e.ssn = d.essn and months_between(sysdate,e.bdate) <= all(select months_between(sysdate, e2.bdate) from employee e2, department d2
*
ERROR at line 3:
ORA-00904: invalid column name

could someone tell me why?
thankyou soo much

At the end of your third line you put "(sysdate,e2.bdate)"; only you call upon e2 on the next line: from employee e2 ...