Try this
$json = $_POST['json'];
$count=0;
$array = json_decode($json, true);
foreach ($array['person'] as $item){
$age= $item['age'];
$name= $item['name'];
$sql = "insert into Test4Upload(age,name) values('$age','$name')";
if(mysql_query($sql))
{
$count++;
}
}
return $count;