data2.php

<?php
//setting header to json
header('Content-Type: application/json');

//database
define('DB_HOST', 'localhost');
define('DB_USERNAME','root');
define('DB_PASSWORD','');
define('DB_NAME','smartseptic tank');

//get connection
$mysqli = new mysqli(DB_HOST, DB_USERNAME, DB_PASSWORD, DB_NAME);

if(!$mysqli){
    die("Connection failed: ". $mysqli->error);
}

//query to get data from the table
//$query = sprintf("SELECT moisture, LightIntensity, Temperature, Humidity, timestamp FROM moisture ORDER BY ID DESC  LIMIT 8");
$query = sprintf("SELECT Septic_Level FROM septic1 ORDER BY ID DESC LIMIT 1");

//execute query
$result = $mysqli->query($query);

//loop through the returned data
$data = array();
foreach($result as $row){
    $data[] = $row;
}

//free memory associated with result
$result->close();

//close connection
$mysqli->close();

//now print data
print json_encode($data);