How to find rows that contain string in plsql function - sql

Question

When i try to implement the function to find if rows contain a string.
The function always return 0.
This is my function
member function containsText (pString1 varchar2, pString2 varchar2)return integer is
checked integer;
begin
if INSTR(pString2,pString1)=0 then checked := 0;
else checked := 1 ;
end if;
return checked;
end containsText;
i implement the function like below,
containsText (table_name.column_name, 'some_string_here');
it returns 0.
2 i try to find out why it doesn't work by using the code below,
containsText('abcdefg','fg');
it returns 0 as well.
i try instr method alone, it works
instr('abcdefg','fg');
it returns 6.
i use instr in query to implement my original idea
select instr(table_name.column_name,'Great') from table_name
it works. How could i make this function working as my expect?

Answer 1

Try
member function containsText (pString1 varchar2, pString2 varchar2)return integer is
checked integer;
begin
if INSTR(pString1, pString2)=0 then checked := 0;
else checked := 1 ;
end if;
return checked;
end containsText;
You change in INSTR(pString1, pString2)=0

Answer 2

You have the arguments to INSTR reversed. Also you have a MEMBER function but do not appear to be using any features that would require this. You could use:
Oracle Setup:
CREATE TYPE test_obj AS OBJECT(
value VARCHAR2(20),
MEMBER FUNCTION checkText(
self IN OUT test_obj,
match IN VARCHAR2
) RETURN NUMBER
);
/
CREATE TYPE BODY test_obj IS
MEMBER FUNCTION checkText(
self IN OUT test_obj,
match IN VARCHAR2
) RETURN NUMBER
IS
BEGIN
RETURN LEAST( INSTR( self.value, match ), 1 );
END;
END;
/
Testing:
DECLARE
v_test test_obj := test_obj( 'abcdefgh' );
BEGIN
DBMS_OUTPUT.PUT_LINE( v_test.checkText( 'gh' ) );
DBMS_OUTPUT.PUT_LINE( v_test.checkText( 'i' ) );
END;
/
Outputs:
1
0
db<>fiddle here
You could also write it without the SELF argument and taking two strings (as you've done in the question) but there does not seem to be much point of making this a MEMBER function of a type and it could just be a global stored-function or a STATIC function of the type.
CREATE TYPE test_obj AS OBJECT(
unused_value VARCHAR2(20),
MEMBER FUNCTION checkText( -- could be STATIC FUNCTION
value IN VARCHAR2,
match IN VARCHAR2
) RETURN NUMBER
);
/
CREATE TYPE BODY test_obj IS
MEMBER FUNCTION checkText( -- could be STATIC FUNCTION
value IN VARCHAR2,
match IN VARCHAR2
) RETURN NUMBER
IS
BEGIN
IF INSTR( value, match ) = 0 THEN
RETURN 0;
ELSE
RETURN 1;
END IF;
END;
END;
/
Then:
DECLARE
v_test test_obj := test_obj( 'xyz' );
BEGIN
DBMS_OUTPUT.PUT_LINE( v_test.checkText( 'abcdefgh', 'gh' ) );
DBMS_OUTPUT.PUT_LINE( v_test.checkText( 'abcdefgh', 'x' ) );
END;
/
Outputs:
1
0
db<>fiddle here