MIxed Query

[Gary Ehrenfeld]

How can I combine these into one query? I want to display the total days also.

SELECT DATEDIFF(MAX(Meter_Time), MIN(Meter_Time)) as totaldays
FROM meter

SELECT Historic_Glucose, Scan_Glucose FROM meter

$total_both = $total_historic + $total_scan;
$average = $total_both/$recordcount;
$a1c = (46.7 + $average) / 28.7;
echo '<div class="container">';
echo 'Total Days: ' . $totaldays;
echo 'Record Count: ' . $recordcount . '<br>';
echo 'Average: ' . round($average). '<br>';
echo 'A1c: '.round($a1c,1);
echo '</div>';

Thanks
Gary