<?php

if($izbor==1){upit=mysql_query("SELECT * FROM regija_zapad WHERE kolicina>=1")}
if ($izbor==2){upit=mysql_query("SELECT * FROM regija_istok WHERE kolicina>=1")}
if($izbor==3){upit=mysql_query("SELECT * FROM regija_sjever WHERE kolicina>=1")}
if ($izbor==4){upit=mysql_query("SELECT * FROM regija_jug WHERE kolicina>=1")}
...
?>