Adding function to sum values in custom field

Ok, I made some progress. I should have recognized the problem was on the input earlier. I was using a plugin called Custom Fields. If I used the built in wordpress custom fields, it now works, or at least it is outputting the proper array of numbers.

Previously every edit was appending a new entry to the array.

I’ll post results in a bit after I play some more.

Much appreciate your help!!!!

Ok, so the problem was definitely the plugin. By using the default custom field entry ‘shop_hours’ in posts, I am able to get the appropriate behavior. The total is working properly. I finally cleaned up my code, and my next thought is to implement the same code by category. I don’t think I can use the current select statement to do so though… any thoughts?

/*
The following functions will be used to total all session hours by post
using the custom field 'shop_hours'
Subsequent functions will work for specific categories.
*/

// Function totals all session hours
function total_hours() {
    global $wpdb;
    $total_hours=0;
    $meta_key = 'shop_hours';//set this to your custom field meta key
    $allhours=$wpdb->get_col($wpdb->prepare("SELECT meta_value FROM $wpdb->postmeta WHERE meta_key = %s", $meta_key));
    foreach ($allhours as $hours) {
            $total_hours = $total_hours + $hours;
    }
    return $total_hours;
}

// Total of all hours by category
// Total hours for empennage (cat id = 3)
function emp_hours() {
    global $wpdb;
    $emp_hours=0;
    $meta_key = 'shop_hours';//set this to your custom field meta key
    $allhours=$wpdb->get_col($wpdb->prepare("SELECT meta_value FROM $wpdb->postmeta WHERE meta_key = %s", $meta_key));
    foreach ($allhours as $hours) {
        $emp_hours = $emp_hours + $hours;
    }
    return $emp_hours;
}

// Shortcodes for all hour total functions
add_shortcode('total-hours','total_hours'); // Total
add_shortcode('emp-hours','emp_hours'); // Empennage (cat id = 3)