Dynamic SQL help!

Question

I'm trying to build a update statement with different operator which setup from a table and passed. Not sure how to build it. Please help
PROCEDURE my_update
  p_id            IN NUMBER,
  p_var1          IN NUMBER,
  my_value        IN VARCHAR2,
  my_operator     IN VARCHAR2,
  x_return_status OUT VARCHAR2,
  x_errors        OUT VARCHAR2
) IS
  l_dynamic_string VARCHAR2(4000);
BEGIN
l_dynamic_string := table_b.col2 ||
                    rec.my_operator  /* value as: "=" OR "LIKE" */ ||
                    my_value /* VALUE AS "2233"  OR "900%" */
  UPDATE table_b
     SET col1 = ''
   WHERE id = p_id
     AND l_dynamic_string
     AND id = (SELECT table_a.id
                 FROM table_a
                WHERE id = p_id
                  AND col_a = p_var1);
EXCEPTION
  WHEN OTHERS THEN
    NULL;
END my_update;

Answer 1

Hi,
What you posted can probably be done without dynamic SQL. If the expression after LIKE does not conatin a wild-card, then LIKE behaves just like =. You can probably arrange things so that the query always uses LIKE.
If you need dynamic SQL, then use EXECUTE IMMEDIATE to perform it.
I think you want something like this:
PROCEDURE my_update
  p_id            IN NUMBER,
  p_var1          IN NUMBER,
  my_value        IN VARCHAR2,
  my_operator     IN VARCHAR2,
  x_return_status OUT VARCHAR2,
  x_errors        OUT VARCHAR2
) IS
  l_dynamic_string VARCHAR2 (4000);
  l_update_txt        VARCHAR2 (4000);
BEGIN
    l_dynamic_string := table_b.col2 || ' '     -- If my_operator is LIKE you'll need a space here
                                    || my_operator               /* value as: "=" OR "LIKE" */
                         || Q'< '>'
                         || my_value            /* VALUE AS "2233"  OR "900%" */
                         || Q'<' >'
    l_update_txt := 'UPDATE table_b'
                || '   SET col1 = NULL'
              || ' WHERE id = p_id'
                || '   AND ' || l_dynamic_string
                || '   AND id = (SELECT table_a.id'
                 || '                     FROM table_a'
                 || '             WHERE id = p_id
                 || '               AND col_a = p_var1)';
    dbms_output.put_line (l_update_txt || ' = l_update_txt in my_update');
--  EXECUTE IMMEDIATE  l_update_txt;
--     No EXCEPTION hider
END my_update;While writing dynamic SQL, it's a good idea to display the dynamic text. I used put_line to do that. Remember to comment out (or remove) the display code when testing is finished.
Notice that the EXECUTE IMMEDIATE command is commented out. Only after you've tested some, and you think l_update_txt is correct, should you un-commnet that line.
Never say "EXCEPTION WHEN OTHERS THEN NULL;"
Error messages help you, especially duting development when you're likely to have lots of coding errors.
If you really need to keep the program running after encountering certain errors, then it's okay to have an EXCEPTION block, but your use of either "WHEN OTHERS" or "THEN NULL" should be very limited, and you should not use both of them together.