Search PHP/MySQL with Pagination - php

Question

I wrote this code to search in rows of the table:
<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 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
$page_max = 8;
if (isset($_POST['search'])){
$search = $_POST['searchValue'];
$entriesInDatabase = $database->getData("SELECT count(id) FROM customers WHERE name LIKE '%$search%'");
$numberOfPages = ceil($entriesInDatabase['count(id)']/$page_max);
$numberOfRecords = $page_max;
if(isset($_GET['page'])) {
$page = $_GET['page'];
$start = $page * $page_max;
}
else{
$page = 0;
$start = $page * $page_max;
}
$customers = $database->getUsers("SELECT * FROM customers WHERE name LIKE '%$search%' LIMIT $start, $numberOfRecords");
}
else{
$entriesInDatabase = $database->getData("SELECT count(id) FROM customers");
$numberOfPages = ceil($entriesInDatabase['count(id)']/$page_max);
$numberOfRecords = $page_max;
if(isset($_GET['page'])) {
$page = $_GET['page'];
$start = $page * $page_max;
}
else{
$page = 0;
$start = $page * $page_max;
}
$customers = $database->getUsers("SELECT * FROM customers LIMIT $start, $numberOfRecords");
}
foreach($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=$id' class='btn btn-sm btn-info'><i class='fa fa-info'></i></a></td>
</tr>";
}
?>
</tbody>
</table>
<ul class="pagination">
<?php
if(isset($_GET['page']) && $_GET['page'] > 0){
$previous = $_GET['page'] - 1;
echo '<li class="page-item"><a class="page-link" href="?page='. $previous.'">Previous</a></li>';
}
for($i = 0; $i < $numberOfPages; $i++){
echo '<li class="page-item"><a class="page-link" href="?page='. $i . '">'. $i. '</a></li>';
}
if(isset($_GET['page']) && $_GET['page'] < $numberOfPages - 1){
$page = $_GET['page'];
$next = $page + 1;
echo '<li class="page-item"><a class="page-link" href="?page='.$next.'">Next</a></li> ';
}
elseif(!isset($_GET['page'])){
echo '<li class="page-item"><a class="page-link" href="?page=1">Next</a></li> ';
}
?>
</ul>
</div>
Searching works fine when I'm on page 0, but when I'm at page 2 I can only search for records on that page (I think this is because of the limit in my query) besides that when I search for 'A' it returns 7 pages but if I click on the seconde page it won't load the search results but the main list with customers on page 2.
Could anyone help me fix these issues?

Answer 1

First of all: sanitize your input. Using POST or GET in database queries can be very, very dangerous.
Second: DRY, you probably can do this with half the code you are using.
The reason why you are "losing" your search is because your pagination doesn't carry over the search term.
Add it to the links in the pagination and switch from POST to GET:
<?php
$searchString = '';
if($_GET['searchValue']){
$searchString = '&searchValue=' . $_GET['searchValue'];
}
if(isset($_GET['page']) && $_GET['page'] > 0){
$previous = $_GET['page'] - 1;
echo '<li class="page-item"><a class="page-link" href="?page='. $previous.$searchString.'">Previous</a></li>';
}
// more code
'... href="?page='.$i.$searchString'" ...'
'... href="?page='.$next.$searchString'" ...'
Note that I use $_GET['searchValue'] instead of POST. in most cases there is no advantage in using POST for searches (quite the opposite, if you use GET you can track it in Google Analytics f.ex.). So make sure you change your form method to get and if (isset($_POST['search'])){ to $_GET['searchValue']. If you insist on using POST, you can use $_REQUEST, which holds values from GET and POST.