PHP - Moved: Validate User Entry To Have No Spaces.

Hi, I was just trying to post form data to MySQL and trying to also post value of logged in user? but that code below doesnt work..Do you see a typo? or is it done some other way?

$uid =$_SESSION[ "uid" ]; 

$sql = "INSERT INTO Date (uid) VALUES (:uid)"; 
$query= $conn->prepare( $sql ); 
$query->execute( array( ':uid'=>$uid) );

I'm creating a newsletter and the unsubscribe isn't deleting the database entry like I'm asking it to. Everything else works fine, it even successfully says the user has been removed, but it doesn't actually delete the database entry.

I've spent  two days trying to figure out why. Here's the code:

Newsletter sign up:
 

<?php
//DB Connect Info
$servername = "";
$database = "";
$username = "";
$password = "";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $database);

// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}

/*$createTable = $conn->prepare ("CREATE TABLE IF NOT EXISTS email_user (
  id int(11) NOT NULL AUTO_INCREMENT,
  email varchar(200) NOT NULL,
  hash varchar(250) NOT NULL,
  PRIMARY KEY (id)
)");

$createTable->execute();
*/

function input_security($data)
{
    $data = trim($data);
    $data = stripslashes($data);
    $data = htmlspecialchars($data);
    return $data;
}

$email = input_security($_POST['email']);

$insertData = input_security($insertData);

if(isset($_POST['submit']))
{  
  extract($_POST);
  if($email!="") :
    $email=mysqli_real_escape_string($conn,$email);
    $emailval = '/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,4})$/';    
    if(preg_match($emailval, $email)) :
      $db_check=$conn->query("SELECT * FROM email_user WHERE email='$email'");
      $count=mysqli_num_rows($db_check);
      if($count< 1) :         
         $hash=md5($email.time());
         $link = '/unsubscribe.php?key='.$hash;

        // Change your domain        
         $fetch=$conn->query("INSERT INTO email_user(email,hash) VALUES('$email','$hash')");
         $to="$email"; //change to ur mail address
         $strSubject="Maintenance Fee Relief, LLC | Email Subscription";
         $message = '<p>Thank you for subscribing with us.</p>' ;              
         $message .= '<p>Click here to unsubscribe your email : <a href="'.$link.'">unsubscribe</p>' ;              
         $headers = 'MIME-Version: 1.0'."\r\n";
         $headers .= 'Content-type: text/html; charset=iso-8859-1'."\r\n";
         $headers .= "From: info@";            
         $mail_sent=mail($to, $strSubject, $message, $headers);  
         $msg_sucess="Your request has been accepted!.";
      else :
        $msg="This $email email address is already subscribe with us.";
      endif;  
    else :
      $msg="Please enter your valid email id";
    endif;      
  else :
    $msg="Please fill all mandatory fields";
  endif;
}
?>

<div class="newsletter-sign-up-header-form">
<div id="logerror"><?php echo @$msg; ?><?php echo @$msg_sucess; ?></div>
<form  method="post">
<span><input type="email" name="email" placeholder="Email Address - Join Newsletter" class="newsletter-sign-up-header-email" required></span>
<span><button name="submit" value="submit" title="Submit" class="newsletter-sign-up-header-submit-button">Submit</button></span>
</form>
</div>

<?php
//DB Connect Info
$servername = "";
$database = "";
$username = "";
$password = "";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $database);

// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
?>

<?php
if(@$_GET['key']!=""):
    $hash=mysqli_real_escape_string($conn,$_GET['key']);
    $fetch=$conn->query("SELECT * FROM email_user WHERE hash = '$hash'");
    $count=mysqli_num_rows($fetch);
    if($count==1) :
      $row=mysqli_fetch_array($fetch);      
        $conn->query("DELETE email_user WHERE id='$user_id'");
        $msg="Your email id unsubscribe with us";
    else :
      $msg="Please click valid link.";
    endif;
else :
    header("Location:404.php");
endif;
?>

<!doctype html>
<html lang="en">
<head>
   <title>Unsubscribe</title>
</head>
<body>
    <div align="center">
    <h2><?php echo $msg; ?></h2>
        <a href="https://www.--.com">--.com</a>                                                
    </div>