Dynamic query...but I want to maintain performance.

Question

Say I have a simple PL/SQL PROC like this...
PROCEDURE some_proc(p_id IN NUMBER)
IS
v_fn VARCHAR2(100);
BEGIN
SELECT first_name INTO v_fn
FROM tblEmployees
WHERE id = p_id;
dbms_output.put_line('Name is: ' || v_fn);
END;
Now let's say I want to accept another param in the proc which dictates the order...
Looking at the example below, what would be the best way to dynamically allow the query to change depending on what the user passes in the p_order_col parameter? For example, let's say the user passes "last_name" as the parameter...I would want the query to be:
SELECT first_name
FROM tblEmployees
WHERE id = p_id
ORDER BY last_name;
PROCEDURE some_proc(p_id IN NUMBER, p_order_col IN VARCHAR2)
IS
v_fn VARCHAR2(100);
BEGIN
SELECT first_name INTO v_fn
FROM tblEmployees
WHERE id = p_id;
dbms_output.put_line('Name is: ' || v_fn);
END;
Bear in mind I want to make sure that this query maximizes efficiency. I am wondering if by making the order by clause dynamic, it will make too many Hard Parses and not make use of binding. What I am really looking for here is some sort of DBA/performance expert advice on the right way to do this and not fill up the SGA by doing it the wrong way. I don't simply want to know how to do it...looking for the right way. I was thinking that maybe I could use dbms_sql package and open a cursor, then call .parse to my dynamic query string, then .bind_variable for the p_id. Is that the right start?

Answer 1

Thank you for the quick reply. Theoretically it could be any number of columns. I tried to use a simple example, but in reality it would have to be dynamic for a few reasons...
1) My example is not so simple...to explain it here would take a lot of time...however tblEmployees is a huge query in reality...I was just trying to simplify for my post.
2) I need to order by on possibly multiple rows and that order needs to be dynamic.
I like your decode suggestions, but unfortunately I can't use it here.
Would doing something like this still allow me to make use of binds? Granted, I realize every query which has a different order by clause would qualify as a different query.
v_cursor INTEGER;
v_emp_name VARCHAR2(100);
v_cursor := dbms_sql.open_cursor;
dbms_sql.parse(v_cursor,'SELECT first_name AS emp_name FROM tblEmployees WHERE id = :p_id ORDER BY ' || p_order_col,dbms_sql.native);
dbms_sql.bind_variable(v_cursor, ':p_id', p_id);
dms_sql.define_column(v_cursor,1,v_emp_name);
v_rows := dbms_sql.execute(v_cursor);
LOOP
IF dbms_sql.fetch_rows(v_cursor) = 0 THEN
EXIT;
END IF;
dbms_sql.column_value(v_cursor,1,v_emp_name);
END LOOP;
dbms_sql.close(v_cursor);
dbms_output.put_line('Name: ' || v_emp_name);