How does pagination done with PHP + AJAX?

In this example, AJAX actually displays records 6 in 6, but all are loaded. If there were a thousand records, for example, it would be a problem.

A simple alternative is to prepare a php page containing a limited SELECT to X records. You must pass by parameter the page number that will be displayed and the page will return the records.

The SQL command can be this way (php):

$mysqli->query('SELECT * FROM tabela ORDER BY id DESC LIMIT '.$inicio.','.$limite.'');

The return of this search will be the records in the given range. To learn how it works: link .

You should return this query as an array for AJAX. You can understand how to do this here: link .

But for pagination to work, you must compute the $ start variable.

To calculate this start, you can do this:

$limite = 3; // Limite de registros por paginação
$pagina = (isset($_GET['page']))? $_GET['page'] : 1; // Recebe o número da paginação por método GET
$inicio = ($limite * $pagina) - $limite; // Cálculo do início

You can also get the total number of pages:

$result = $mysqli->query("SELECT * FROM tabela");
$total = $result->num_rows; // Quantidade total de registros
$numPaginas = ceil($total/$limite); // Quantidade total de páginas

In pagination, the SELECT used in the database must use LIMIT to tell you how many records to fetch and OFFSET to tell you how many records to skip. In the link you posted does not tell you how SELECT is done, it just mounts a Javascript array to use as a sample.

  

Another question: How can I change the array in the example by a SELECT, so I can use a mysqli_fetch_array to fetch each record line?

Your ajax request will call a PHP script, this script will in turn fetch the data in the database using the method you want, be it PDO, mysql, mysqli, etc.

For PHP to know how many records to jump in the SELECT, you need to enter the page number that the user wants to see, this parameter will be sent by AJAX to the PHP script.

Example displaying 10 records per page
The URL of the ajax will be "script.php? Pagina = 1", "script.php? Pagina = 2", "script.php? Pagina = 3", etc ...

// No script.php:
$registrosPorPagina = 10;
$pagina             = intval($_GET['pagina']);

// Calcula o offset de acordo com o número da página
$offset             = $pagina == 1 ? 0 : ($pagina * $registrosPorPagina) - $registrosPorPagina;

// Comando SELECT dinâmico, sempre irá buscar só 10 registros de acordo com a página
// offset 0: registros 1-10
// offset 1: registros 11-20
// offset 2: registros 21-30
$sql = "SELECT * FROM tabela LIMIT 10 OFFSET {$offset}";