Lets assume, I have a string that holds a query string.
How can I select the rows from that query string in oracle ?
I tried execute immediate but it returns nothing.
declare
hello varchar(30000);
begin
hello:='select * from test_table';
execute immediate hello;
end;
You would use a dynamic cursor.
Here's an example with SQL*Plus:
SQL> var dyn_cur refcursor
SQL> DECLARE
2 l_sql_query VARCHAR2(1000);
3 BEGIN
4 -- complex function that returns a query:
5 l_sql_query := 'SELECT 1, dummy FROM dual';
6 OPEN :dyn_cur FOR l_sql_query;
7 END;
8 /
PL/SQL procedure successfully completed.
SQL> print dyn_cur
1 DUM
---------- ---
1 X
You can use dynamic cursors in PL/SQL procedures and packages:
SQL> CREATE OR REPLACE PROCEDURE prc_dyn_cur(p_dyn_cursor OUT SYS_REFCURSOR) IS
2 BEGIN
3 OPEN p_dyn_cursor FOR 'SELECT 1, dummy FROM dual';
4 END;
5 /
Procedure created.
SQL> exec prc_dyn_cur(:dyn_cur);
PL/SQL procedure successfully completed.
SQL> print dyn_cur
1 DUM
---------- ---
1 X
declare
hello varchar(30000);
type tb is table of test_table$rowtype;
mytb tb;
begin
hello:='select * from test_table';
execute immediate hello bulk collect into mytb;
-- now you got all og youe data in the "array" mytb
end;
notice that this solution takes into account that you know what table you are selecting from. plus, i think you should describe what exactly it is you are trying to achieve.
CREATE OR REPLACE PROCEDURE query_executer (string_query IN VARCHAR)
IS
c1 SYS_REFCURSOR;
v_last_name employees.last_name%TYPE; -- Selecting last_name
BEGIN
OPEN c1 FOR string_query; -- Opening c1 for the select statement
LOOP
FETCH c1 INTO v_last_name;
DBMS_OUTPUT.put_line (v_last_name);
EXIT WHEN (C1%NOTFOUND);
END LOOP;
END;
SET SERVEROUTPUT ON
EXECUTE query_executer('select last_name from employees');
OUTPUT
Procedure created.
Abel
Ande
Atkinso
PL/SQL procedure successfully completed.
