sql มัน query ช้ามากๆเลยคับ ทำยังไงคับ ช่วยที่คับขอบคุณคับ

include("db.inc.php"); 
$objConnect = mysql_connect("localhost","root","Network_10"); 
$objDB = mysql_select_db("dhcpv2"); 
$_POST["sroom"]="31";
function returndata() 
{
$strSQL = "SELECT ip_address FROM wire_device WHERE room='".$_POST["sroom"]."' order by ip_address ASC ";         $objQuery = mysql_query($strSQL); 
$resultArray = array(); 
while($obResult = mysql_fetch_array($objQuery)) 
{ 
array_push($resultArray, $obResult); 
}
return $resultArray; 
}
$resultDA = returndata(); 
foreach ($resultDA as $result)
{
 $result = mysqli_query($DBConn,"SELECT ip_address, DATETIME, ping_status FROM wire_log WHERE ip_address ='".$result["ip_address"]."' AND ping_status='1' ORDER BY DATETIME DESC limit 1");
 }