Maalesef bu şekilde yardımcı olamam. Kod şeklinde paylaşın.
		
		
	 
<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
ob_start();
session_start();
include 'baglan.php';
if(isset($_POST["kayit_yap"])){
    $k_adsoyad = isset($_POST['k_adsoyad']) ? $_POST['k_adsoyad'] : ""; 
    $k_tc = isset($_POST['k_tc']) ? $_POST['k_tc'] : "";  
    $k_password = isset($_POST['k_password']) ? $_POST['k_password'] : ""; 
    $k_email = isset($_POST['k_email']) ? $_POST['k_email'] : ""; 
    $k_no = isset($_POST['k_no']) ? $_POST['k_no'] : ""; 
    if(strlen($k_tc) != 11 || strlen($k_no) != 11) {
        echo "Tc Kimlik No ve Tel No 11 haneden fazla ya da 11 haneden küçük olamaz.";
        exit; 
    } 
    $sorgu = $db->prepare('INSERT INTO kullanici SET
        k_adsoyad = ?,
        k_tc = ?,
        k_password = ?,
        k_email = ?,
        k_no = ?
    ');
    
    $ekle = $sorgu->execute([
        $k_adsoyad, 
        $k_tc, 
        $k_password,
        $k_email,
        $k_no
    ]);
    
    if ($ekle) {
        header('location: uyegirisi.php?durum=basarili');
        exit; 
    } else {
        $hata = $sorgu->errorInfo();
        echo 'MySQL hatası: ' . $hata[2];
        exit; 
    }
}
if(isset($_POST["giris_yap"])){
    $k_tc = $_POST['k_tc']; 
    $k_password = $_POST['k_password'];
    $kullanici_sorgu = $db->prepare("SELECT * FROM kullanici WHERE k_tc=:k_tc AND k_password=:k_password");
    $kullanici_sorgu->execute([
        'k_tc' => $k_tc,
        'k_password' => $k_password
    ]);
    
    $say = $kullanici_sorgu->rowCount();
    if($say == 1) {
        $_SESSION['k_tc'] = $k_tc;
        header('location: anasayfa.php?durum=basarili');
        exit; 
    } else { 
        header('location: uyegirisi.php?durum=basarisizgiris');
        exit; 
    }
    
}
error_reporting(E_ALL);
ini_set("display_errors", 1);
ob_start();
session_start();
include 'baglan.php';
if(isset($_POST["ravdevu"])){
    $r_tarih = isset($_POST['tarih']) ? $_POST['tarih'] : ""; 
    $r_saat = isset($_POST['zaman']) ? $_POST['zaman'] : "";  
    $r_oda = isset($_POST['Oda']) ? $_POST['Oda'] : ""; 
    $r_alet = isset($_POST['Alet']) ? $_POST['Alet'] : ""; 
    $r_spor = isset($_POST['Spor']) ? $_POST['Spor'] : ""; 
    $spor_id = isset($_POST['kullanici_id']) ? $_POST['kullanici_id'] : ""; 
    $kaydet = $db->prepare("INSERT INTO randevular (r_tarih, r_saat, r_oda, r_alet, r_spor, spor_id) VALUES (?, ?, ?, ?, ?, ?)");
    $insert = $kaydet->execute([
        $r_tarih,
        $r_saat,
        $r_oda,
        $r_alet,
        $r_spor,
        $spor_id
    ]);
    if($insert) {
        header('location: anasayfa.php?durum=basarili');
        exit; 
    } else {  
        header('location: anasayfa.php?durum=basarisiz');
        exit;
    }
}
?>
<!DOCTYPE html>
<html lang="tr">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="randevuBilgisi.css">
    <title>Spor Otomasyon</title>
</head>
<body>
<div class="ust_bar">
    <a href="anasayfa.php"><h1>Spor Otomasyon</h1></a> 
    <div class="menu">
        <a href="anasayfa.php"><h5>Ana Sayfa</h5></a> 
        <a href="uyelik.php"><h5>Üyelik Bilgileri</h5></a> 
        <a href="Paket.php"><h5>Paket Bilgileri</h5></a> 
        <a href="Ekipman.php"><h5>Ravdevu </h5></a> 
        <a href="RandevuBilgisi.php"><h5>Randevu Bilgisi</h5></a> 
        <a href="Antreman.php"><h5>Antreman Bilgileri</h5></a>
    </div>
</div>
<table>
<tr>
<th class="kutucuk">Tarih</th>
<th class="kutucuk">Saat</th>
<th class="kutucuk">Oda</th>
<th class="kutucuk">Alet</th>
<th class="kutucuk">Spor</th>
</tr>
<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
ob_start();
session_start();
include 'baglan.php';
$randevular_sor = $db->prepare("SELECT * FROM randevular 
INNER JOIN kullanici ON randevular.spor_id = kullanici.k_id WHERE k_tc=:k_tc");
$randevular_sor->execute([
    'k_tc' => $_SESSION['k_tc']
]);
while ($randevular_cek = $randevular_sor->fetch(PDO::FETCH_ASSOC)) { ?>
<tr>
<td><?php echo $randevular_cek['r_tarih']; ?></td>
<td><?php echo $randevular_cek['r_saat']; ?></td>
<td><?php echo $randevular_cek['r_oda']; ?></td>
<td><?php echo $randevular_cek['r_alet']; ?></td>
<td><?php echo $randevular_cek['r_spor']; ?></td>
</tr>
<?php } ?>
</table>
<div class="cikis">
    <a href="index.php">Çıkış Yap</a>
</div>
</body>
</html>
    <?php 
error_reporting(E_ALL);
ini_set("display_errors", 1);
ob_start();
session_start();
include 'baglan.php';
    ?>
    <!DOCTYPE html>
    <html lang="tr">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <link rel="stylesheet" href="Ekipman.css">
        <title>Spor Otomasyon</title>
    </head>
    <body>
    <div class="ust_bar">
        <a href="anasayfa.php"><h1>Spor Otomasyon</h1></a> 
        <div class="menu">
            <a href="anasayfa.php"><h5>AnaSayfa</h5></a> 
            <a href="uyelik.php"><h5>Uyelik Bilgileri</h5></a> 
            <a href="Paket.php"><h5>Paket Bilgileri</h5></a> 
            <a href="Ekipman.php"><h5>Ravdevu </h5></a> 
            <a href="RandevuBilgisi.php"><h5>Randevu Bilgisi</h5></a> 
            <a href="Antreman.php"><h5>Antreman Bilgileri</h5></a>
        </div>
    </div>
    <div class="cikis">
        <a href="index.php">Çıkış Yap</a>
    </div>
    <div class="adSoyad">
        <p><b>Sn Kullanıcı lütfen randevu seçiniz</b></p>
        </div>
    <div class="orta_bar" id="O_Randevu_div">
        <form action="islem.php" method="POST">
        <input type="date" name="tarih">
        <input type="time" name="zaman">
        <select name="Oda" id="Oda" class="Oda">  
    <option value="">Seçin</option>
    <option value="Oda1">Oda1</option>
    <option value="Oda2">Oda2</option>
    <option value="Oda3">Oda3</option>
    <option value="Oda4">Oda4</option>
    <option value="Oda5">Oda5</option>
    <option value="Oda6">Oda6</option>
</select>
<select name="Alet" id="Alet" class="Alet">
    <option value="">Seçin</option>
    <option value="Koşu Bandı">Koşu Bandı</option>
    <option value="Bisiklet">Bisiklet</option>
    <option value="Vücut Geliştirme Makineleri">Vücut Geliştirme Makineleri</option>
    <option value="Kaykay">Kaykay</option>
    <option value="Plates Topu">Plates Topu</option>
    <option value="Sandalye Dips">Sandalye Dips</option>
    <option value="Sandalye Dips">Sandalye Dips</option>
</select>
<select name="Spor" id="Spor" class="Spor">
    <option value="">Seçin</option>
    <option value="Futbol">Futbol</option>
    <option value="Basketbol">Basketbol</option>
    <option value="Kriket">Kriket</option>
    <option value="Tenis">Tenis</option>
    <option value="Beyzbol">Beyzbol</option>
    <option value="Atletizm">Atletizm</option>
</select>
    <input type="hidden" name="kullanici_id" value="<?php echo $kullanici_cek['kullanici_id']; ?>">
    <button name="ravdevu">Kaydet</button>
        </form>
    </body>
    </html>