问仅当在表上进行选择并给出结果时才运行SQL脚本。如果没有给出结果，则不应运行SQL脚本

EN

IF ( select count(1) from  ( _your selection_ ) a ) > 0 THEN
_RUN your script_;
END IF

DECLARE
type t1
IS
  TABLE OF hr.employees.first_name%type;
  t11 t1;
BEGIN
  SELECT e.first_name bulk collect
  INTO t11
  FROM hr.employees e
  WHERE E.EMPLOYEE_ID=999;
  IF(t11.count!      =0) THEN
    FOR i           IN 1..t11.count/*here you can write your own query */
    LOOP
      dbms_output.put_line(t11(i));
    END LOOP;
  ELSE
    dbms_output.put_line('oh..ho..no rows selected' );
  END IF;
END;
/