Can't call a function inside another function

Question

Hello,
i have the following function :
FUNCTION test_day_week (P_DATE DATE)
RETURN VARCHAR2 IS
BEGIN
RETURN TO_CHAR(P_DATE ,'DAY');
END;
--it returns the day name of a given date
FUNCTION TEST_DAY_NUMBER (P_DAY_NAME VARCHAR2)
RETURN NUMBER IS
     V_RESULT NUMBER;
     V_RETURN_DAY VARCHAR2(30);
     P_DATE DATE;
BEGIN
V_RETURN_DAY := test_day_week (P_DATE );
MESSAGE('V_RETURN_DAY'|| V_RETURN_DAY);
MESSAGE('V_RETURN_DAY'|| V_RETURN_DAY);
IF V_RETURN_DAY = 'MONDAY' THEN V_RESULT :=1;
     END IF ;
IF V_RETURN_DAY = 'TUSEDAY' THEN V_RESULT :=2;
     END IF ;
IF V_RETURN_DAY = 'WENDSDAY' THEN V_RESULT :=3;
     END IF ;
IF V_RETURN_DAY = 'THURSDAY' THEN V_RESULT :=4;
     END IF ;
IF V_RETURN_DAY = 'FRIDAY' THEN V_RESULT :=5;
     END IF ;                
IF V_RETURN_DAY = 'SATURDAY' THEN V_RESULT :=6;
END IF ;
IF V_RETURN_DAY = 'SUNDAY' THEN V_RESULT :=7;
     END IF ;
RETURN V_RESULT;
END;
--The above function returnds the day name in numbers
The proble is that when i call test_day_week function it returns no value even it is tested separatly and works fine don't know where is my problem :
1-number of argrments in function[b] TEST_DAY_NUMBER
?? and so ..!
Regards,
Abdetu..

Answer 1

You could also cut the whole thing down to a simple function... (assuming you have a need to customise your start of week rather than use built in date functionality)
SQL> ed
Wrote file afiedt.buf
  1  CREATE OR REPLACE FUNCTION test_day_week (P_DATE DATE) RETURN NUMBER IS
  2  BEGIN
  3    RETURN (INSTR('MONTUEWEDTHUFRISATSUN',TO_CHAR(P_DATE,'DY'))+2)/3;
  4* END;
SQL> /
Function created.
SQL> select test_day_week(sysdate) from dual;
TEST_DAY_WEEK(SYSDATE)
                     1
SQL> select test_day_week(sysdate+1) from dual;
TEST_DAY_WEEK(SYSDATE+1)
                       2
SQL> select test_day_week(sysdate+2) from dual;
TEST_DAY_WEEK(SYSDATE+2)
                       3
SQL> select test_day_week(sysdate+3) from dual;
TEST_DAY_WEEK(SYSDATE+3)
                       4
SQL> select test_day_week(sysdate+4) from dual;
TEST_DAY_WEEK(SYSDATE+4)
                       5
SQL> select test_day_week(sysdate+5) from dual;
TEST_DAY_WEEK(SYSDATE+5)
                       6
SQL> select test_day_week(sysdate+6) from dual;
TEST_DAY_WEEK(SYSDATE+6)
                       7
SQL> select test_day_week(sysdate+7) from dual;
TEST_DAY_WEEK(SYSDATE+7)
                       1
SQL>