如何基于发布的值和结果运行SQL查询，重定向到其他页面或执行下一组代码？

Question

I am working on a site and there's a point at which you can choose to Sign in or Sign out, but I need to be able to run a query to determine if the previous clocking was an In or and Out so that the user can't double clock in or out. I am using PHP to accomplish this.

Here is where I am now but I'm not sure if this is correct, and I'm not sure how to assign the InOrOut to a value to compare it to whether it = 'In' or 'Out'

$query = $pdo->prepare("SELECT TOP 1 InOrOut FROM visitor WHERE email = ? ORDER BY clocking DESC");
$email = $_POST['email'];
$query->execute(array($email,'InOrOut'));

This is for the Sign In page. If the previous clocking was an 'In', then I want to redirect to the Sign out page.

If the previous clocking was not an 'In', then continue with the remainder of the query which is below.

//SQL query to be run
$query = $pdo->prepare("SELECT email,firstname,lastname,coname FROM visitor WHERE email = ?");
//Assign variable $email to the POSTed value from inmail.php
$email = $_POST['email'];
$email = filter_var ($email, FILTER_SANITIZE_EMAIL);
//Executes and stores the results of the query to be fetched in in.php
$query->execute(array($email,'firstname'));

UPDATE:

I tried the following and did not get any errors, but it didn't do anything either. Worked like it normally does instead of redirecting. I put the following in it's own php file and made it a required asset. Still not sure if I'm pulling the result in correctly.

<?php
//TESTING  possibly create new PHP and require it on in.php
$query = $pdo->prepare("SELECT TOP 1 InOrOut FROM visitor WHERE email = ? ORDER BY clocking DESC");
$email = $_POST['email'];
$query->execute();
$result= $query->fetchAll(PDO::FETCH_ASSOC);
if($result == 'In')
{
    echo '<script type="text/javascript">alert("It works.");</script>';
    header("Location: ../outmail.html",TRUE,302);
}


?>

Once a user hits sign in using their email, the sign in page posts to another page which has the following assets.

<!-- Accesses the connection file and assigns the input 'email to $email. Runs the query and returns the matching results' -->
<?php
require 'assets/dbinfo.php';
require 'assets/clockin.php';
require 'assets/indb.php';
?>

Answer 1

Finally got it working with the following code. I create two new php files, one for clock in and one for clock out and added it as an asset to my main page. Thanks for taking a look!

$query = $pdo->prepare("SELECT TOP 1 * FROM visitor WHERE email = ? ORDER BY clocking DESC");
$email = $_POST['email'];
$inout = 'InOrOut';
$query->execute(array($email,'firstname'));
$result = $query->fetchColumn(7);
if($result == 'Out')
{
    $message = "You have already signed out, redirecting you to sign in page.";
echo "<script type='text/javascript'>alert('$message');</script>";
echo "<script>setTimeout(\"location.href = '../inmail.php';\",0);</script>";
}
?>

Answer 2

Use Single Query TO execute

$query = $pdo->prepare("SELECT * FROM visitor WHERE email = ? ORDER BY clocking DESC");
$email = $_POST['email'];
$query->execute();
$result= $query->fetchAll(PDO::FETCH_ASSOC);

if(count($result) > 0)
{
// Previous clocking Not an In
}
else
{
// Previous clocking an In
}