<?php
$time_start = microtime(true);

$serverName = "localhost";
$connectionOptions = [
    "Database" => "SampleDB",
    "Uid" => "sa",
    "PWD" => "your_password",
];
// Establishes the connection
$conn = sqlsrv_connect($serverName, $connectionOptions);

// Read Query
$tsql = "SELECT SUM(Price) as sum FROM Table_with_5M_rows";
$getResults = sqlsrv_query($conn, $tsql);
echo("Sum: ");
if ($getResults == false) {
    die(FormatErrors(sqlsrv_errors()));
}
while ($row = sqlsrv_fetch_array($getResults, SQLSRV_FETCH_ASSOC)) {
    echo($row['sum'] . PHP_EOL);
}
sqlsrv_free_stmt($getResults);

function FormatErrors($errors)
{
    /* Display errors. */
    echo "Error information: ";

    foreach ($errors as $error) {
        echo "SQLSTATE: " . $error['SQLSTATE'] . "";
        echo "Code: " . $error['code'] . "";
        echo "Message: " . $error['message'] . "";
    }
}

$time_end = microtime(true);
$execution_time = round((($time_end - $time_start) * 1000), 2);
echo 'QueryTime: ' . $execution_time . ' ms';