$sql="INSERT INTO Persons (FirstName, LastName, Age)
            VALUES
            ('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";

            if (!mysql_query($sql,$con))
              {
              die('Error: ' . mysql_error());
              }
            echo "1 record added";

            mysql_close($con)

<?php
            // connect database  code
             $dbhost ='localhost';
            $dbuser = 'tomking';
            $dbpass = 'ansoftsys';
            $dbname = 'ansoftsysdb';
            //connectivity of database
            $conn = mysql_connect($dbhost,$dbuser,$dbpass) or die ('Error Connecting to mysql');
            mysql_select_db($dbname);
          ?>

$mysqli = new mysqli($hostname, $username, $password, $database_name);

if($mysqli->error)
    die($mysqli->error);

$mysqli->query("SET NAMES 'UTF8'");

$query = "INSERT INTO my_table VALUES ('value_1', 'value_2')";
$mysqli->query($query);
if(!$mysql->error)
   echo 'do something';

$query = "SELECT * FROM my_table";
$sql = $mysqli->query($query);
if($sql->num_rows > 0) {
    while($row = $sql->fetch_assoc()) {
        echo $row['field_1'];
    }
}
$sql->close();