How to compare a boolean value returned from a function in a sql query

Question

Hi all
i have a function which return boolean true or false.
mean while i am writing a sql query which should check this function and will return a result set only when it is true. how will i use a function which returns boolean in a sql query..
thanks in advance'
Hari

Answer 1

I don't think this is possible - i'm not sure. Can you post your function script? The reason why am i asking this is --
satyaki>set serveroutput on
satyaki>
satyaki>
satyaki>
satyaki>create or replace function test_satf(emno in number)
  2  return boolean
  3  is
  4    v_cnt   number(5);
  5    v_flg   boolean;
  6  begin
  7    select count(*)
  8    into v_cnt
  9    from emp
10    where empno = emno;
11   
12    if v_cnt = 1 then
13       v_flg := TRUE;
14    else
15       v_flg := FALSE;
16    end if;
17   
18    return v_flg;
19  exception
20    when others then
21      v_flg := FALSE;
22   return v_flg;
23  end;
24  /
Function created.
satyaki>
satyaki>
satyaki>
satyaki>
satyaki>
satyaki>desc emp;
Name                                      Null?    Type
EMPNO                                     NOT NULL NUMBER(4)
ENAME                                              VARCHAR2(10)
JOB                                                VARCHAR2(9)
MGR                                                NUMBER(4)
HIREDATE                                           DATE
SAL                                                NUMBER(7,2)
COMM                                               NUMBER(7,2)
DEPTNO                                             NUMBER(2)
satyaki>
satyaki>
satyaki>
satyaki>select count(*) from emp;
  COUNT(*)
        14
satyaki>
satyaki>select empno,test_satf(empno)
  2  from emp;
select empno,test_satf(empno)
ERROR at line 1:
ORA-06552: PL/SQL: Statement ignored
ORA-06553: PLS-382: expression is of wrong type
satyaki>select to_char(test_satf(empno))
  2  from emp;
select to_char(test_satf(empno))
ERROR at line 1:
ORA-06552: PL/SQL: Statement ignored
ORA-06553: PLS-382: expression is of wrong type
satyaki>
satyaki>create or replace function test_satf(emno in number)
  2  return varchar2
  3  is
  4    v_cnt   number(5);
  5    v_flg   varchar2(10);
  6  begin
  7    select count(*)
  8    into v_cnt
  9    from emp
10    where empno = emno;
11   
12    if v_cnt = 1 then
13       v_flg := 'TRUE';
14    else
15       v_flg := 'FALSE';
16    end if;
17   
18    return v_flg;
19  exception
20    when others then
21      v_flg := 'FALSE';
22   return v_flg;
23  end;
24  /
Function created.
satyaki>
satyaki>
satyaki>select test_satf(empno)
  2  from emp;
TEST_SATF(EMPNO)
TRUE
TRUE
TRUE
TRUE
TRUE
TRUE
TRUE
TRUE
TRUE
TRUE
TRUE
TEST_SATF(EMPNO)
TRUE
TRUE
TRUE
14 rows selected.Or, may be i'm missing something.
Regards.
Satyaki De.