Answers for "php create json from string"

php json_encode

$person = array( 
    "name" => "Johny Carson", 
    "title" => "CTO"
); 
$personJSON=json_encode($person);//returns JSON string

how to receive json data in php

$data = json_decode(file_get_contents('php://input'), true);
print_r($data);
echo $data;

return json in php

//code igniter
$query="qry";
$query = $this->db->query($query);
$res=$query->result();
return json_encode($res);