How can I create a json object in php - php

Question

I am working in android and php.
I want to return a json object to android program from php program.
If these is a entry in a database then it is working properly. But when there is no record in database then it goes wrong.
I would welcome suggestions
I want to make json object like this ([{"id":"5"}])
This is my php program:-
$server = "localhost";
$username = "root";
$password = "";
$database = "mymusic";
$con = mysql_connect($server, $username, $password) or die ("Could not connect: " . mysql_error());
mysql_select_db($database, $con);
$id=$_GET["id"];
$pass=$_GET["password"];
//$id='ram';
//$pass='ram';
$sql = "SELECT id FROM login where userid='$id' and password='$pass'";
$result = mysql_query($sql) or die ("Query error: " . mysql_error());
$records = array();
if (mysql_num_rows($result)==0)
{
//what should i right here to make jsonobject like this:- ([{"id":"5"}])
echo myjsono;
}
else
{
while($row = mysql_fetch_assoc($result))
{
$records[] = $row;
}
echo $_GET['jsoncallback'] . '(' . json_encode($records) . ');';
}
?>

Answer 1

How about something like this: (replace with your own variables)
if (empty($row)){
$arr = array('success' => 'false');
} else {
$arr = array('success' => 'true');
}
echo json_encode($arr);

Answer 2

If you want your android app to receive an object with a special id in the case of a not found condition I would return this:
{"id":"0"}
Then in your android app check if the id == 0 and that will tell you no records were found.

Answer 3

This is very correct solution for my question:-
$server = "localhost";
$username = "root";
$password = "";
$database = "mymusic";
$con = mysql_connect($server, $username, $password) or die ("Could not connect: " . mysql_error());
mysql_select_db($database, $con);
$id=$_GET["id"];
$pass=$_GET["password"];
//$id='ram';
//$pass='ram';
$sql = "SELECT id FROM login where userid='$id' and password='$pass'";
$result = mysql_query($sql) or die ("Query error: " . mysql_error());
$records = array();
if (mysql_num_rows($result)==0)
{
// {"messages":{"message":[{"id": "17","user": "Ryan Smith","text": "This is an example of JSON","time": "04:41"}]};}
**echo '('.'['.json_encode(array('id' => 0)).']'.')';** //**note this**
}
else
{
while($row = mysql_fetch_assoc($result))
{
$records[] = $row;
}
mysql_close($con);
echo $_GET['jsoncallback'] . '(' . json_encode($records) . ');';
}
//mysql_close($con);
//echo $_GET['jsoncallback'] . '(' . json_encode($records) . ');';
?>