Originally posted by carloscm
Thx gandolf989.

Actually the result of the first SQL becomes a column of the second SQL.

I understand explicit cursor need to be closed or remain opened and I've done that. The thing is, the explicit cursor has closed while the implicit cursor, which is the first SQL(with open cursor statement), remains opened!!

If it is an implicit one, I could have no control over it after used, right.

Please correct me if I'm wrong, thx.
Try to close it and find out. Also make sure that cursors get closed in the exceptions section and reraise any unhandled errors.

This is an example of an implicit cursor.

Code:
   FOR v_row IN ( SELECT v_count AS count
                 FROM table_b
                WHERE ... )
   LOOP
      do something
   END LOOP;

END;
/