How to generate .json file with PHP?

Here is a sample code:

<?php 
$sql="select * from Posts limit 20"; 

$response = array();
$posts = array();
$result=mysql_query($sql);
while($row=mysql_fetch_array($result)) { 
  $title=$row['title']; 
  $url=$row['url']; 

  $posts[] = array('title'=> $title, 'url'=> $url);
} 

$response['posts'] = $posts;

$fp = fopen('results.json', 'w');
fwrite($fp, json_encode($response));
fclose($fp);


?> 

Use this:

$json_data = json_encode($posts);
file_put_contents('myfile.json', $json_data);

You have to create the myfile.json before you run the script.

Insert your fetched values into an array instead of echoing.

Use file_put_contents() and insert json_encode($rows) into that file, if $rows is your data.