How to create search function in PHP/MySQL - php

Question

I wrote this code:
<div class="container mx-auto">
<!--Add class table-responsive for responsive table -->
<div class="row">
<div class="col-md-6">
<form method="post">
<div class="input-group">
<input size='14' type="text" class="form-control" placeholder="Search for..." name="searchValue">
<span class="input-group-btn">
<button class="btn btn-secondary" name='search' type="submit"><i class="fa fa-search"></i></button>
</span>
</div>
</form>
</div>
</div>
<table class="table mx-auto" id="'table">
<thead>
<tr>
<th>Name</th>
<th>Surname</th>
<th>Email</th>
<th>Phone</th>
<th>Company</th>
<th>More</th>
</tr>
</thead>
<tbody>
<?php
$pagination = new Pagination(7);
$page_max = $pagination->getPageMax();
$start = $pagination->getStart();
if(!isset($_POST['search'])) {
$numberOfPages = $pagination->numberOfPages($database->getData("SELECT count(id) FROM customers"));
$customers = $database->getDataAsArray("SELECT * FROM customers LIMIT $start, $page_max");
}
else{
$searchValue = '%'. $_POST['searchValue'] . '%';
$numberOfPages = $pagination->numberOfPages($database->getData("SELECT count(id) FROM customers WHERE name LIKE '$searchValue' "));
$customers = $database->getDataAsArray("SELECT * FROM customers WHERE name LIKE '$searchValue' LIMIT $start, $page_max");
}
foreach($customers as $customer){
$name = $customer ['name'];
$surname = $customer['surname'];
$email = $customer['email'];
$phone = $customer['phone'];
$company = $customer['company'];
$id = $customer['id'];
echo "<tr>
<td>$name</td>
<td>$surname</td>
<td>$email</td>
<td>$phone</td>
<td>$company</td>
<td><a href='customerInfo.php?id=$id' class='btn btn-sm btn-info'><i class='fa fa-info'></i></a></td>
</tr>";
}
?>
</tbody>
</table>
<ul class="pagination">
<?php
echo $pagination->previous($numberOfPages);
for($i = 0; $i < $numberOfPages; $i++){
echo '<li class="page-item"><a class="page-link" href="?page='. $i . '">'. $i. '</a></li>';
}
echo $pagination->next($numberOfPages);
?>
</ul>
</div>
I want to search in my table, this works fine so far but when I search on A for example and I click my pagination page 1 it rebuilds the page with all te records from the database.
I tried to add a parameter to the url upon button click but upon creating this button with link the searchValue is still null.
This question is not about my sql query. It's about searching with pagination
Could anyone help me fix this?