Error in comparision of year part of date in writting query

Question

i am writing a Stored procedure in which i have to compare year
part from system date to that of a table column in which of date type this my requirement
this is only a part of my stored procedure
set serveroutput on
declare
p_RN varchar(10);
begin
Select Cast(NVL(Count(Patientid),0) as Nvarchar2(10))
into p_RN from Patient where (TempPatFlag=0 or temppatflag is NULL)
and *( select extract (year from Registration_Date) from Patient;) = (select extract ( year from sysdate ) from dual;);* -- this is where i have compared year
end;
but if i run this below query runs fine
select extract ( year from sysdate ) from dual;

Answer 1

Hi,
This is basically the same idea Hoek posted, I don't think either is significantly faster than the other, but you may find some things clearer in one than in the other:
  select cast(nvl(count(patientid),0) as nvarchar2(10))
  into   p_rn
  from   patient
  where  NVL (temppatflag, 0)              = 0
  and    TRUNC (registration_date, 'YEAR') = TRUNC (sysdate, 'YEAR');You don't need the dual table very much in PL/SQL. For this job, you wouldn't need dual in pure SQL, either.