oracle - Using bind variables with dynamic SELECT INTO clause in PL/SQL

Question

I have a question regarding where bind variables can be used in a dynamic SQL statement in PL/SQL.

For example, I know that this is valid:

CREATE OR REPLACE FUNCTION get_num_of_employees (p_loc VARCHAR2, p_job VARCHAR2) 
RETURN NUMBER
IS
  v_query_str VARCHAR2(1000);
  v_num_of_employees NUMBER;
BEGIN
  v_query_str := 'SELECT COUNT(*) FROM emp_' 
                 || p_loc
                 || ' WHERE job = :bind_job';                           
  EXECUTE IMMEDIATE v_query_str
    INTO v_num_of_employees
    USING p_job;
  RETURN v_num_of_employees;
END;
/

I was wondering if you could use a bind variables in a select statement like this

CREATE OR REPLACE FUNCTION get_num_of_employees (p_loc VARCHAR2, p_job VARCHAR2) 
RETURN NUMBER
IS
  v_query_str VARCHAR2(1000);
  v_num_of_employees NUMBER;
BEGIN
  v_query_str := 'SELECT COUNT(*) INTO :into_bind FROM emp_' 
                 || p_loc
                 || ' WHERE job = :bind_job';                           
  EXECUTE IMMEDIATE v_query_str
    USING out v_num_of_employees, p_job;
  RETURN v_num_of_employees;
END;
/

Note I used a SELECT INTO statement as my dyamic string and used a bind variable in the INTO clause.

I am currently travelling right now and won't have access to my computer back at home for a few days, but this has been nagging me for a bit. Tried reading the PL/SQL reference but they don't have an example of a select like this.

Thanks

Answer 1

In my opinion, a dynamic PL/SQL block is somewhat obscure. While is very flexible, is also hard to tune, hard to debug and hard to figure out what's up. My vote goes to your first option,

EXECUTE IMMEDIATE v_query_str INTO v_num_of_employees USING p_job;

Both uses bind variables, but first, for me, is more redeable and tuneable than @jonearles option.