$wpdb update query in plugin only updating one column

Question

I am doing an update in from woocommerce admin, edit order details. I have two problems:

1. Only column 'download-count' is updated.
2. I am not able to catch any sql errors.

However, when using the same query in a standalone php file, it works fine. What is wrong, and how can I get hold of the sql errors, or at least the query sent?

$table = $wpdb->prefix . 'woocommerce_downloadable_product_permissions';
$expiry_date = date("Y-m-d", strtotime("+ 30 days"));
$expiry_time = $expiry_date . ' 00:00:10';

$wpdb->query("UPDATE `$table` SET 
    `downloads_remaining` = '1',
    `access_expires` = '$expiry_time',
    `download_count` = (`download_count` + 1)
    WHERE `order_id` = '$post_id'");

---

Here is "standalone php version, which works:

$link = mysqli_connect($servername, $username, $password, $db);
$post_id = '219';

if (!$link) { exit; }

$expiry_date = date("Y-m-d", strtotime("+ 30 days"));
$expiry_time = $expiry_date . ' 00:00:00';
$table = 'hkmw_woocommerce_downloadable_product_permissions';
$query = "UPDATE `$table` SET 
    `downloads_remaining` = '1',
    `access_expires` = '$expiry_time',
    `download_count` = (`download_count` + 1)
    WHERE `order_id` = '$post_id';";

if (!mysqli_query($link,$query)) {
    printf("Errormessage: %s\n", mysqli_error($link));
}
mysqli_close($link);

Answer 1

I had to use two separate queries. The $wpdb->update syntax cant deal with calculating based on the existing value. But for the other two fields it works. So like this:

$table = $wpdb->prefix . 'woocommerce_downloadable_product_permissions';

$expiry_date = date("Y-m-d", strtotime("+ 30 days"));
$expiry_time = $expiry_date . ' 00:00:00';

$wpdb->query("UPDATE $table SET 
    download_count = (download_count + 1)
    WHERE order_id = '$post_id'");

$wpdb->update( $table, array( 'downloads_remaining' => '1', 'access_expires' => $expiry_time), array( 'order_id' => $post_id ), array( '%s', '%s' ), array( '%d' ) );