How to output result of SELECT statement which is

Question

I have a string which contains SQL SELECT statement.
I wonder how can I output result of the execution of that statement on the screen, execution will be done using native dynamic SQL (EXECUTE IMMEDIATE).

example:

DECLARE
v_stmt VARCHAR2 := 'SELECT * FROM employees';
BEGIN
EXECUTE IMMEDIATE v_stmt; -- ??? how to output result of that select on the screen.
END;

Important remark: structure of table can be any. I have to write a procedure which accepts name of the table as parameter, so I can't hardcode a table structure and don't want to do it.

Thanks for responses. Any ideas very appreciated/

Answer 1

If you can change that execute immediate into a dbms_sql cursor, then the following solution should be able to help you, as you can get the column names from a dbms_sql cursor:

https://forums.oracle.com/forums/thread.jspa?threadID=700648

Answer 2

If you are on Oracle 12c with a 12c client, this should work:

declare
    rc sys_refcursor;
begin
    open rc for 'select * from dual';
    dbms_sql.return_result(rc);
end;

Answer 3

Yes we can execute select statement dynamically.

Let say we have a table test. It has four column Row_id,Name,Rank etc When we do select * from test; Result will be

Row_id Name   Rank  
1      R1    5 
2      R2    1 
3      R3    2 
4      R4    4 

Now we can use DBMS_SQL package to execute dynamically SELECT Sql Statament.

Code is below:

   DECLARE
        v_CursorID  NUMBER;
        v_table VARCHAR2(50):='test';
        v_SelectRecords  VARCHAR2(500);
        v_NUMRows  INTEGER;
        v_MyNum INTEGER;
        v_Myname VARCHAR2(50);
        v_Rank INTEGER;



    BEGIN
         v_CursorID := DBMS_SQL.OPEN_CURSOR;
        v_SelectRecords := 'SELECT * from ' || v_table ;
        DBMS_SQL.PARSE(v_CursorID,v_SelectRecords,DBMS_SQL.V7);
        DBMS_SQL.DEFINE_COLUMN(v_CursorID,1,v_MyNum);
        DBMS_SQL.DEFINE_COLUMN(v_CursorID,2,v_Myname,50);
        DBMS_SQL.DEFINE_COLUMN(v_CursorID,3,v_Rank);

        v_NumRows := DBMS_SQL.EXECUTE(v_CursorID);
   LOOP
        IF DBMS_SQL.FETCH_ROWS(v_CursorID) = 0 THEN
             EXIT;
        END IF;

        DBMS_SQL.COLUMN_VALUE(v_CursorId,1,v_MyNum);
        DBMS_SQL.COLUMN_VALUE(v_CursorId,2,v_Myname);
        DBMS_SQL.COLUMN_VALUE(v_CursorId,3,v_Rank);



        DBMS_OUTPUT.PUT_LINE(v_MyNum || ' ' || v_Myname || ' ' || v_Rank  );

   END LOOP;

   EXCEPTION
        WHEN OTHERS THEN
                  RAISE;
        DBMS_SQL.CLOSE_CURSOR(v_CursorID);
        end;