Count(*) does not take into consideration the where condition

Question

the following sql function is supposed to calculate the number of rows that respect the conditions in the where clause. After I call this function I get the the total number of rows in the table. Any help would be much appreciated.
FUNCTION NBRTRIMCOMPLETES (ETU_NO NUMBER, PRG_NO NUMBER) RETURN VARCHAR2 IS
nbrTrimCompletes number(6);
begin
     SELECT COUNT(*) into nbrTrimCompletes from (select * from INSCRIPTION I WHERE I.ETU_NO = ETU_NO AND I.PRG_NO = PRG_NO);
     RETURN nbrTrimCompletes;
end NBRTRIMCOMPLETES;

Answer 1

The compile can't distinguish between the column name ETU_NO an the variable ETU_NO, that's why your where condition always evaluates to true.
Change the name of the parameters.
FUNCTION NBRTRIMCOMPLETES (P_ETU_NO INSCRIPTION.ETU_NO%TYPE,
                           P_PRG_NO INSCRIPTION.PRG_NO%TYPE
                          ) RETURN NUMBER
IS
  nbrTrimCompletes PLS_INTEGER;
begin
  SELECT COUNT(*)
  into   nbrTrimCompletes
  FROM   INSCRIPTION I
  WHERE  I.ETU_NO = P_ETU_NO
  AND    I.PRG_NO = P_PRG_NO;
  RETURN nbrTrimCompletes;
end NBRTRIMCOMPLETES;