PHP搜索栏导致页面加载错误

I had a page loading data from my mysql database working and showing the data correctly, but after attempting to implement a search function there is now an error attempting to load the page.

Below is my html code I added for the search bar (this is in the file PhysicianSearch.php):

<form action="PhysicianSearch.php" method="post">
  <input type="text" placeholder="Search.." name="ValueToSearch">
  <input type="submit" name="search" value="Filter"><br><br>
</form>

below is the php code I added for the search bar (this is in the file PhysicianSearch.php):

<?php
  if(isset($_POST['search'])) {
      $valueToSearch = $_POST['valueToSearch'];
      $query = "SELECT * FROM Physician WHERE CONCAT('physicianID', 'firstName', 'lastName', 'yearNum', 'yearNum', 'position', 'isAttending', 'highRiskTrained') LIKE '%" . $valueToSearch ."%'";
      $search_result = filterTable($query);

  } else {
    $query = "select * from Physician";
    $search_result = filterTable($query);

  }

  function filterTable($query) {
    $connect = mysqli_connect("localhost", "root", "password", "dbName");
    $filter_results = mysqli_query($connect, $query);
    return $filter_results

  }
?>

Your input name is ValueToSearch where the PHP code is checking for valueToSearch

Make sure they have the same case