Can we use variables inside FOR-IN loop - oracle

Question

Below code is self explanatory. Can we use variables inside a FOR-IN loop in PL/SQL?
This is requirement because the query inside the FOR-IN needs to be dynamic in nature.
SET SERVEROUT ON;
DECLARE
STMNT varchar2(4000);
SELECT_SQL varchar2(4000);
BEGIN
SELECT_SQL := q'[select table_name from all_tables where owner='EMP' and table_name like 'TEMP_%']';
FOR REC IN (SELECT_SQL) LOOP
dbms_output.put_line (REC.table_name);
END LOOP;
END;

Answer 1

No, you cannot use for loop to navigate through a result set returned by a dynamically built query. But, what you cant do is to open a refcursor for that dynamically built query and use LOOP or WHILE loop construct to go through result set. Here is a simple example, though in your situation, there is no need to use dynamic SQL at all:
set serveroutput on;
clear screen;
declare
l_sql_statement varchar2(4000); -- going to contain dynamically built statement
l_rcursor sys_refcursor; -- ref cursor
l_owner varchar2(100); -- variable that will contain owner's name
l_res_tab_name varchar2(100); -- variable we will fetch table name into
begin
l_owner := 'NK';
l_sql_statement := 'select table_name
from all_tables
where owner = :1'; -- bind variable
open l_rcursor for l_sql_statement
using dbms_assert.simple_sql_name(l_owner); -- slight protection from
-- SQL injection
loop
fetch l_rcursor into l_res_tab_name; -- fetch table name from the resultset
exit when l_rcursor%notfound; -- exit, when there is nothing to fetch
dbms_output.put_line(l_res_tab_name); -- print table name
end loop;
end;
Result:
anonymous block completed
TEST1
TEST2
TMP_TEST
ERR$_T1
Note: Consider, in this situation, not to use dynamic SQL at all, there's really no need for it. Table names and column names are known at compile time, only right side of the predicates changes.