<?php
//company_name verisi
$company_name = "deneme";

// company_name sorgulaması
$sorgu = $baglanti->prepare("SELECT * FROM tablo WHERE company_name = :company_name");
$sorgu->bindParam(":company_name", $company_name, PDO::PARAM_STR);
$sorgu->fetchAll(PDO::FETCH_ASSOC);
$sorgu->execute();

if($sorgu->rowCount()) {
// var
echo "var";
} else {
// yok
echo "yok";
}
?>