MySql删除查询根本不执行

So I have user submitted info passed through the url that then goes into a form and they hit submit if they want to delete this record but the delete query is not executing?

Here is my code:

<?php   
$unique_id = $_SESSION['unique_id'];
$date = $_GET['date'];
  $steps = $_GET['steps']; }  ?>

          <h2>Delete Steps</h2>

        <div class="form">
            <form id="deletesteps" action="deletesteps.php" method="post" autocomplete="off">

              <div class="field-wrap">
                <label>
                  Date:
                </label>
                <input type="date" required autocomplete="off" name="date" value="<?php echo $date ?>" readonly="readonly"/>
                </div>

              <div class="field-wrap">
                <label>
                  Steps:
                </label>
                <input type="number" required autocomplete="off" name="steps" value="<?php echo $steps ?>" readonly="readonly"/>
                </div>
              <div class="field-wrap">
                <button type="submit" class="button button-block" name="submit" />Delete?</button>
              </div>
            </form>
        </div>


        <?php 
        if(isset($_POST['submit'])){

        $sql = $link->query("DELETE FROM step_count WHERE steps = '$steps' AND date = '$date' AND unique_id = '$unique_id'");

        header('Location: nextpage.php'); }  ?>

Can try the below:

<?php 
 if(isset($_POST['submit'])){
 $date = $_POST['date'];
 $steps = $_POST['steps'];
 $sql = $link->query("DELETE FROM step_count WHERE steps = '$steps' AND date = '$date' AND unique_id = '$unique_id'");

//first you should know , what date format comes from Php code in $_GET['date'].
// if date format is -  28/02/2018
$date = date("Y-m-d", strtotime(str_replace('/', '-', $_GET['date'])));

Try the following

<?php
if( isset( $_POST['submit'], $_POST['steps'], $_POST['date'], $_POST['_token'] ) ){
    if( $_SESSION['_token'] != $_POST['_token'] ) die( 'Invalid token!' );
    $date = strtotime( $_POST['date'] );
    $steps = intval( $_POST['steps'] );
    $unique_id = intval($_SESSION['unique_id']);
    $sql = $link->query("DELETE FROM step_count WHERE steps = '$steps' AND UNIX_TIMESTAMP(date) = '$date' AND unique_id = '$unique_id'");
    echo "Deleted:" . $sql? 'Yes':'No';

}else{
    if( isset( $_GET['date'], $_GET['steps'] ) ){
        $_SESSION['_token'] = uniqid();
        ?>
<h2>Delete Steps</h2>
<div class="form">
    <form id="deletesteps" action="deletesteps.php" method="post" autocomplete="off">
        <input type="hidden" name="_token" value="<?php echo $_SESSION['_token'] ?>">
        <div class="field-wrap">
            <label>
                Date:
            </label>
            <input type="date" required autocomplete="off" name="date" value="<?php htmlentities( $date ) ?>" readonly="readonly"/>
        </div>
        <div class="field-wrap">
            <label>
                Steps:
            </label>
            <input type="number" required autocomplete="off" name="steps" value="<?php echo htmlentities($steps) ?>" readonly="readonly"/>
        </div>
        <div class="field-wrap">
            <button type="submit" class="button button-block" name="submit" />Delete?</button>
        </div>
    </form>
</div>
        <?php
    }else{
        die('date and steps are required!');
    }
}