datatables + lengthMenu + All + serverside processing + handling -1/All - php

Question

this is a basic datatables fiddle
this is a basic datatables fiddle with lengthMenu
What I want to do is get this working in my serverside processing example.
I can get the dropdown to appear right doing the following to my index.php file.
$(document).ready(function() {
var dataTable = $('#employee-grid').DataTable({
"lengthMenu": [
[10, 25, 50, -1],
[10, 25, 50, "All"]
],
"processing": true,
"serverSide": true,
"ajax": {
url: "employee-grid-data.php", // json datasource
type: "post", // method , by default get
error: function() { // error handling
$(".employee-grid-error").html("");
$("#employee-grid").append('<tbody class="employee-grid-error"><tr><th colspan="3">No data found in the server</th></tr></tbody>');
$("#employee-grid_processing").css("display", "none");
}
}
});
});
So that works okay if I select 10, 25 or 50 but if I select All I get No data found in the server.
So my issue is in my employee-grid-data.php file,noted here, and this is where I am having my difficulty. I need to do an if statement to handle this All option or -1 as this is what I pass to the server when I select All in $requestData['length']
I have identified the 2 areas where I use $requestData['length'] and this I belive to be the issue.
$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 , $requestData['start'] contains start row number ,$requestData['length'] contains limit length.
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get employees"); // again run query with limit
So what I have to do is try and write such that:
if $requestData['length'] NOT equals -1
do this line
else
do this line without using $requestData['length'] as a parameter.
This is where I am having difficulty.
This is my attempt, but this could be a syntax issue or something else. I'm not very good at debugging this.
if ($requestData['length']!==-1){
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']." LIMIT ".$requestData['start']." ,".$requestData['length']." ";
} else {
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']
}
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get employees");
When I visit the page index.php I get No data found in the server and in the console I get 500 (Internal Server Error).
Can anyone advise what my code should look like?
Or how could I debug this?
I would ideally like to be able to add a basic if else statement just to see if I could get that bit right alone, but not sure how to do this in this setup. with Javasecript I would normally use console.log
Here is my entire employee-grid-data.php file for reference:
<?php
/* Database connection start */
$servername = "localhost";
$username = "root";
$password = "Password1";
$dbname = "test";
$conn = mysqli_connect($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 =>'employee_name',
1 => 'employee_salary',
2=> 'employee_age'
);
// getting total number records without any search
$sql = "SELECT employee_name, employee_salary, employee_age ";
$sql.=" FROM employee";
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get employees");
$totalData = mysqli_num_rows($query);
$totalFiltered = $totalData; // when there is no search parameter then total number rows = total number filtered rows.
if( !empty($requestData['search']['value']) ) {
// if there is a search parameter
$sql = "SELECT employee_name, employee_salary, employee_age ";
$sql.=" FROM employee";
$sql.=" WHERE employee_name LIKE '".$requestData['search']['value']."%' "; // $requestData['search']['value'] contains search parameter
$sql.=" OR employee_salary LIKE '".$requestData['search']['value']."%' ";
$sql.=" OR employee_age LIKE '".$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 without limit in the query
if ($requestData['length']!==-1){
$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 , $requestData['start'] contains start row number ,$requestData['length'] contains limit length.
} else {
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']
}
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get employees"); // again run query with limit
} else {
$sql = "SELECT employee_name, employee_salary, employee_age ";
$sql.=" FROM employee";
if ($requestData['length']!==-1){
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']." LIMIT ".$requestData['start']." ,".$requestData['length']." ";
} else {
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']
}
$query=mysqli_query($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["employee_name"];
$nestedData[] = $row["employee_salary"];
$nestedData[] = $row["employee_age"];
$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
?>
edit1 good link for testing http://phpfiddle.org/

Answer 1

This is the code I had to add to handle the $requestData['length'] equaling -1. I had to add wherever I had $requestData['length']. This is the best I could do.
if ($requestData['length'] > 0 ){
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']." LIMIT ".$requestData['start']." ,".$requestData['length']." ";
} else {
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]." ".$requestData['order'][0]['dir']." ";
}