PHP Select Data From MySQL Database

After Inserting data into database you want to display the data that are in database.for that run the below query in php file and display data.  

<?php
include('config.php');
$sql = "SELECT id, firstname, lastname FROM Your_table_name";
$result = $conn->query($sql);

if ($result->num_rows > 0) 
{
    // output data of each row    
   while($row = $result->fetch_array()) 
   {
        echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
    }
}  
else 
{
    echo "0 results";
}

?>
If the data is present in table then the data will be display otherwise "0 results" found error message will be displayed. 

Note: Don't forget to add connection string into your file.