Something

function clean_db(){	$query = "select clean_date from tbl_last_clean";	$result = mysql_query($query);	$row = mysql_fetch_row($result);	if ( empty($row[0]) )	{		$query = "insert into tbl_last_clean(clean_date) values('".time()."')";		$result = mysql_query($query);				if ($result) 			return;		else			echo '[{error:"Error during db clean."}]'; exit;	}	else	{		if( date("d",$row[0]) != date("d",time()) )		{			$query = "delete from tbl_link where expire < '".time()."'";			$result = mysql_query($query);						$query = "update tbl_last_clean set clean_date = '".time()."'";			$result = mysql_query($query);		}		else			return;	}	}