history.php

<?php 
function delOld(){
$db = mysql_connect("localhost","datalogger","datalogger") or die("DB Connect error");
mysql_select_db("datalogger");
$q="delete from datalogger"; 
mysql_query($q);
mysql_close($db); 
return 0;
}

function hist($sensor){ 
$db = mysql_connect("localhost","datalogger","datalogger") or die("DB Connect error"); 
mysql_select_db("datalogger"); 
for ($i=0;$i<=29;$i++) 
{ 
        $q=   "insert into history ( "; 
        $q=$q."select date_add(curdate(),interval $i hour),'$sensor', round(avg(temperature),2),round(avg(humidity),2) "; 
        $q=$q."from datalogger "; 
        $q=$q."where sensor = '$sensor' "; 
        $q=$q."and date_time >=date_add(curdate(),interval $i hour) ";$ii=$i+1; 
        $q=$q."and date_time < date_add(curdate(),interval $ii hour) "; 
        $q=$q.") "; 
        mysql_query($q); 
} 
mysql_close($db); 
return 0; 
} 
hist(4); 
delOld();
?>