PL/SQL Output column results in dbms_output.put_line LOOP

Question

Good morning, I will start out saying that I have already done 97% of this as yes, it is homework. The ONLY part I am confused with is not understanding the Error that is given. I had to create a loop that would take 2 numbers given and then output which numbers both are commonly divisible by. Here is that code:

    SET SERVEROUTPUT ON SIZE UNLIMITED

--DROP TABLE IF IT EXISTS
DROP TABLE TESTER1 cascade constraints;
--CREATE TESTER1 TABLE
CREATE TABLE TESTER1 (xnum number, num1 number, num2 number);
--DECLARE VARIABLES
DECLARE 
   Test_Number1 number := 10;
   Test_Number2 number := 20;
   x number := 1;
--BEGIN   
BEGIN --OUTSIDE LOOP
    LOOP
        BEGIN --INSIDE LOOP
            INSERT INTO TESTER1(xnum,num1,num2)
            VALUES(x,MOD(Test_Number1,x),MOD(Test_Number2,x));
            x := x + 1;
        EXIT WHEN NOT x < 20;
        EXCEPTION
        WHEN OTHERS THEN
            dbms_output.put_line('error');
        END;
    END LOOP; --INSIDE LOOP
END; --OUTSIDE LOOP
/

I then wrote a SELECT statement to find where both have a common divisor:

SELECT xnum FROM tester1
where num1=num2;

My Question is: How do I loop through the results from the table Tester1 and use dbms_output.put_line() so each result from the SELECT statement is inserted until it loops through 3 rows? I hope I explained it well enough. I am using Oracle 12c.

Answer 1

Ok, so the answer I have found and just need to try and incorporate into my previous statement is:

BEGIN
    FOR r_xnum IN (SELECT xnum FROM tester1
where num1=num2)
    LOOP
    dbms_output.put_line('Common factor: ' ||r_xnum.xnum);
    END LOOP;
END;
/

Thanks again for all that pointed me in the right direction. It has been awhile since I posted here last so not sure how to close out the question without completely deleting it, so I will keep it how it is unless someone else knows how. EDIT I have to wait 2 days until I can accept my own answer

Final run:

SET SERVEROUTPUT ON SIZE UNLIMITED

--DROP TABLE IF IT EXISTS
DROP TABLE TESTER1 cascade constraints;
--CREATE TESTER1 TABLE
CREATE TABLE TESTER1 (xnum number, num1 number, num2 number);

--DECLARE VARIABLES
DECLARE 
   Test_Number1 number := '&input1';
   Test_Number2 number := '&input2';
   x number := 1;
--BEGIN   
BEGIN --LOOP 1
    LOOP --LOOP FOR INSERT
        BEGIN --INSIDE LOOP
            INSERT INTO TESTER1(xnum,num1,num2)
            VALUES(x,MOD(Test_Number1,x),MOD(Test_Number2,x));
            x := x + 1;
            EXIT WHEN NOT x < 20;
       END;
    END LOOP; --LOOP 1
        BEGIN --LOOP FOR SELECT
            dbms_output.put_line('The two numbers enetered are ' ||Test_Number1|| 'and '||Test_Number2);
            FOR r_xnum IN (SELECT xnum FROM tester1
                where num1=num2)
            LOOP
                dbms_output.put_line('Common factor: ' ||r_xnum.xnum);
            END LOOP;
        END;
END;
/