select count(*)total, sum(decode( to_char(hiredate, 'yyyy'),'1990', 1, 0 )),
count(decode(extract(year from hiredate),'1981', 1))"1981",
count(decode(extract(year from hiredate),'1982',empno))"1982",
sum(case when to_char(hiredate,'yyyy')='1983' then 1 els 0 end)"1983"
from emp