DataTables server side proccessing warning - php

Question

I am using DataTables, but it is causing an error, and I cannot find where the error is.
I want to use server-side processing, because after inserting 11k Rows, it's lagging.
The code I am using:
<?php
/* Database connection start */
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "accounts";
$conn = mysqli_connect($servername, $username, $password, $dbname) or die("Connection failed: " . mysqli_connect_error());
/* Database connection end */
// storing request (ie, get/post) global array to a variable
$requestData= $_REQUEST;
$columns = array(
// datatable column index => database column name
0 =>'type',
1 => 'country',
2 => 'information',
3 => 'seller',
4 => 'price'
);
// getting total number records without any search
$sql = "SELECT type, country, information, seller, price ";
$sql.=" FROM accounts WHERE type2='1'";
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get employees");
$totalData = mysqli_num_rows($query);
$totalFiltered = $totalData; // when there is no search parameter then total number rows = total number filtered rows.
$sql = "SELECT type, country, information, seller, price ";
$sql.=" FROM accounts WHERE type2='1' AND 1=1";
if( !empty($requestData['search']['value']) ) { // if there is a search parameter, $requestData['search']['value'] contains search parameter
$sql.=" AND ( type LIKE '".$requestData['search']['value']."%' ";
$sql.=" OR country LIKE '".$requestData['search']['value']."%' ";
$sql.=" OR information LIKE '".$requestData['search']['value']."%' )";
$sql.=" OR seller LIKE '".$requestData['search']['value']."%' )";
}
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get employees");
$totalFiltered = mysqli_num_rows($query); // when there is a search parameter then we have to modify total number filtered rows as per search result.
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']." LIMIT ".$requestData['start']." ,".$requestData['length']." ";
/* $requestData['order'][0]['column'] contains colmun index, $requestData['order'][0]['dir'] contains order such as asc/desc */
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get employees");
$data = array();
while( $row=mysqli_fetch_array($query) ) { // preparing an array
$nestedData=array();
$nestedData[] = $row["type"];
$nestedData[] = $row["country"];
$nestedData[] = $row["information"];
$nestedData[] = $row["seller"];
$nestedData[] = $row["price"];
$data[] = $nestedData;
}
$json_data = array(
"draw" => intval( $requestData['draw'] ), // for every request/draw by clientside , they send a number as a parameter, when they recieve a response/data they first check the draw number, so we are sending same number in draw.
"recordsTotal" => intval( $totalData ), // total number of records
"recordsFiltered" => intval( $totalFiltered ), // total number of records after searching, if there is no searching then totalFiltered = totalData
"data" => $data // total data array
);
echo json_encode($json_data); // send data as json format
?>
I am not finding any solutions.
The error that is showing on PHP file

Answer 1

$requestData does not have start and order keys, so use isset() or empty() functions to check if they are not empty, then only use them.
For example:
LIMIT " . (empty($requestData['start']) ?
'whatever you want to put default value' :
$requestData['start'])