// Bu şekilde deneyebilirsiniz.
<?php
if (isset($_POST['gonder'])) {
    $key = $_POST['key'];
    if (empty($_POST['key'])) { ?>
        <center>
            <div class="alert alert-danger" role="alert"><strong><i class="fas fa-ban"></i> Boş Bırakma !</strong> </div>
        </center>
        <?php
    } else {
        include 'baglan/config.php';
        $queries = $db->query("SELECT * FROM ogrkulup WHERE CONCAT(ADI,' ',SOYADI,' ',GELIL) = '{$key}'")->fetchAll(PDO::FETCH_ASSOC);
        if ($queries) {
            foreach ($queries as $query) :
        ?><div class="alert alert-success" role="alert"><strong><i class="fas fa-check"></i> Bilgi Bulundu !</strong> </div>
                <center><strong style="color:red">Detaylar</strong></center>
                <br>
                <center><strong>ADI : <?php echo $query['ADI']; ?></strong>
                    <br>
                    <strong>SOYADI : <?php echo $query['SOYADI']; ?></strong>
                    <br>
                </center>
            <?php
            endforeach;
        } else {
            ?><div class="alert alert-danger" role="alert"><strong><i class="fas fa-ban"></i> Bilgi Bulunamadı !</strong> </div>
<?php
        }
    }
}