select * from table where cate_id in (2,4,8)

------解决方案--------------------
还是用or效率应该更高一些吧,用in写起来更容易一些
PHP code

$a=explode(',',"2,4,8,23,44,");
$w = array();
foreach($a as $s){
  if(intval($s))
    $w[]='cate_id='.intval($s);
}
if(count($w))
  echo "select * from table where ".implode(' or ',$w);