Aşağıdaki haliyle çalıştı istersen bir dene
<?php
$vtsunucu = "localhost";
$vtdbname = "test";
$vtuser = "root";
$vtpassw = "";

try {
$db = new PDO("mysql:host=$vtsunucu;dbname=$vtdbname;charset=utf8",$vtuser, $vtpassw);
$db->query("SET CHARACTER SET utf8");
$db->query("SET NAMES UTF8");
}catch ( PDOException $e ){
print $e->getMessage();
}

?>

// FUNCTION //
<?php

session_start();


$_SESSION['kullaniciid'] = "ryesilirmak";

function say($tablo, $sutun = false, $deger = false, $sutun2 = false, $deger2 = false, $iz = '='){
global $db;
$sql = "SELECT * FROM $tablo";
        
if($sutun2 || $deger2){
            
            $sql .= " WHERE $sutun $iz :$sutun and $sutun2 $iz :$sutun2";
$query = $db->prepare($sql);
$query->execute([":$sutun" => $deger, ":$sutun2" => $deger2,]);
return $query->rowCount();
            
        }elseif($sutun2 == false || $deger2 == false){

$sql .= " WHERE $sutun $iz :$sutun";
$query = $db->prepare($sql);
$query->execute([":$sutun" => $deger]);
return $query->rowCount();

}else{

$query = $db->prepare($sql);
$query->execute();
return $query->rowCount();
}

}

?>

//YAZDIRMA // </br>
<?php echo say('gorevler','kullaniciid',$_SESSION['kullaniciid'],'durum',1 ); ?>