Truncate

 <?php 

$user = "user"; 

$password = "password"; 

$host = "host"; 

$database= "database";

$connection= mysql_connect ($host, $user, $password);

if (!$connection)

{

die ('Could not connect:' . mysql_error());

}

mysql_select_db($database, $connection);

$truncatetable= mysql_query("TRUNCATE TABLE table_name");

if($truncatetable !== FALSE)

{

   echo("All rows have been deleted.");

}

else

{

   echo("No rows have been deleted.");

}

?>