<?php

    $hostname='localhost';
    $username='root';
    $password='';
    $database='jsondb';

    $conn=mysqli_connect($hostname,$username,$password,$database) or die ('Connecting to Mysql failed');

     $jsonCont = file_get_contents('https://graph.facebook.com/186622721684184?fields=posts{id,full_picture,created_time,from,message}&access_token=');

     $content = json_decode($jsonCont, true);
     for($x = 0; $x <= 24; $x++){

     $id = $content['posts']['data'][$x]['id'];
     $message = $content['posts']['data'][$x]['message'];
     $name = $content['posts']['data'][$x]['from']['name'];
     $full_picture = $content['posts']['data'][$x]['full_picture'];
     $created_time = $content['posts']['data'][$x]['created_time'];

    mysqli_query($conn,"insert into fbjsontable value('$id', '$message', '$name', '$full_picture', '$created_time')");
    }

?>

isset($content['posts']['data'][$x]['full_picture'])?$fullpicture=$content['posts']['data'][$x]['full_picture']:$fullpicture='';

isset($content['posts']['data'][$x]['full_picture'])?$fullpicture=$content['posts']['data'][$x]['full_picture']:$fullpicture='Image not found';

$full_picture = $content['posts']['data'][$x]['full_picture'] ?? null;