sqlplus plus program exit control

[jennifer2007]

Hi Friends,

Before, my dba friend was able share a simple sqlplus batch program that has a exit control at the beginning. But I lost the program and I cant remember how to do it again :(

My problem is like this: Say I have a program1.sql

program1.sql
=========

whenever sqlerror exit;

select count(*) from table1 where code='U';

update table2 blah blah....

(more sqlplus programs follows)....

exit;

======================

My question is ...How do I force exit(forced error) the program
if the count(*)=0 for the first code? This means that there is no
transactions to be processed and to save resources just skip the
entire process.

Do you understand why I mean here

Thanks a lot