Calculating SQL query processing

Question

All I want do to is simply get the result of how long (in seconds) the PHP takes to process the SQL query. Am I on a right track? Is my code correct to get the result I want?

<?php
$con = mysql_connect("localhost","root","");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }

mysql_select_db("test3", $con);

    $start = microtime(TRUE);
    $result = mysql_query("SELECT * FROM `test`
    ORDER BY `test`.`test2` DESC
    LIMIT 0,100");


echo "<table border='1'>
<tr>
<th>ID</th>
<th>test1</th>
<th>test2</th>
<th>test3</th>
<th>test4</th>
</tr>";

while($row = mysql_fetch_array($result))
  {
  echo "<tr>";
  echo "<td>" . $row['ID'] . "</td>";
  echo "<td>" . $row['test1'] . "</td>";
  echo "<td>" . $row['test2'] . "</td>";
  echo "<td>" . $row['test3'] . "</td>";
  echo "<td>" . $row['test4'] . "</td>";
  echo "</tr>";
  }
echo "</table>";

$end = microtime(TRUE);

$sqlTime = $end - $start;


mysql_close($con);
echo $sqlTime
?>   

Answer 1

1. Yes, microtime is designed to be used for this. The PHP documentation mentions this use case for microtime().
2. Consider putting this into a loop and print out the average result: if the measured time is too small, you can't provide a reliable estimation.
3. Concerning the MySQL request: you should switch to mysqli or PDO.