in-depth: also checked in OrdersScheduler::import(), but
		// update() can be called directly outside of the import flow.
		if ( OrdersScheduler::is_test_order( $order ) ) {
			return -1;
		}

		$format = array(
			'%d',
			'%d',
			'%s',
			'%s',
			'%s',
			'%s',
			'%d',
			'%f',
			'%f',
			'%f',
			'%f',
			'%s',
			'%d',
			'%d',
		);

		$data = array(
			'order_id'           => $order->get_id(),
			'parent_id'          => $order->get_parent_id(),
			'date_created'       => $order->get_date_created()->date( 'Y-m-d H:i:s' ),
			'date_paid'          => $order->get_date_paid() ? $order->get_date_paid()->date( 'Y-m-d H:i:s' ) : null,
			'date_completed'     => $order->get_date_completed() ? $order->get_date_completed()->date( 'Y-m-d H:i:s' ) : null,
			'date_created_gmt'   => gmdate( 'Y-m-d H:i:s', $order->get_date_created()->getTimestamp() ),
			'num_items_sold'     => self::get_num_items_sold( $order ),
			'total_sales'        => $order->get_total(),
			'tax_total'          => $order->get_total_tax(),
			'shipping_total'     => $order->get_shipping_total(),
			'net_total'          => self::get_net_total( $order ),
			'status'             => self::normalize_order_status( $order->get_status() ),
			'customer_id'        => $order->get_report_customer_id(),
			'returning_customer' => $order->is_returning_customer(),
		);

		$order_fulfillment_status = '';
		if ( FeaturesUtil::feature_is_enabled( 'fulfillments' ) && true === self::has_fulfillment_status_column() && $order instanceof WC_Order ) {
			$order_fulfillment_status   = FulfillmentUtils::get_order_fulfillment_status( $order );
			$data['fulfillment_status'] = ( 'no_fulfillments' !== $order_fulfillment_status ) ? $order_fulfillment_status : null;
			$format[]                   = '%s';
		}

		/**
		 * Filters order stats data.
		 *
		 * @param array $data Data written to order stats lookup table.
		 * @param Order|OrderRefund $order  Order object.
		 *
		 * @since 4.0.0
		 */
		$data = apply_filters( 'woocommerce_analytics_update_order_stats_data', $data, $order );

		if ( 'shop_order_refund' === $order->get_type() ) {
			$parent_order = wc_get_order( $order->get_parent_id() );
			// Refunds attach to the original order. Skip if the parent is another refund.
			if ( $parent_order && ! $parent_order instanceof WC_Order_Refund ) {
				$data['parent_id'] = $parent_order->get_id();
				$data['status']    = self::normalize_order_status( $parent_order->get_status() );

				$refund_type               = $order->get_meta( '_refund_type' );
				$uses_new_full_refund_data = OrderUtil::uses_new_full_refund_data();
				$use_parent_refund_amounts = $uses_new_full_refund_data && (
					'full' === $refund_type
					|| self::should_split_full_refund_using_parent_order( $order, $parent_order )
				);
				if ( $use_parent_refund_amounts ) {
					$data['num_items_sold'] = -1 * self::get_num_items_sold( $parent_order );
					$data['tax_total']      = -1 * $parent_order->get_total_tax();
					$data['net_total']      = -1 * self::get_net_total( $parent_order );
					$data['shipping_total'] = -1 * $parent_order->get_shipping_total();
				}
			}
			/**
			 * Set date_completed and date_paid the same as date_created to avoid problems
			 * when they are being used to sort the data, as refunds don't have them filled
			*/
			$data['date_completed'] = $data['date_created'];
			$data['date_paid']      = $data['date_created'];
		}

		// Update or add the information to the DB.
		$result = $wpdb->replace( $table_name, $data, $format );

		/**
		 * Fires when order's stats reports are updated.
		 *
		 * @param int $order_id Order ID.
		 *
		 * @since 4.0.0.
		 */
		do_action( 'woocommerce_analytics_update_order_stats', $order->get_id() );

		// Check the rows affected for success. Using REPLACE can affect 2 rows if the row already exists.
		return ( 1 === $result || 2 === $result );
	}

	/**
	 * Deletes the order stats when an order is deleted.
	 *
	 * @param int $post_id Post ID.
	 */
	public static function delete_order( $post_id ) {
		global $wpdb;
		$order_id = (int) $post_id;

		if ( ! OrderUtil::is_order( $post_id, array( 'shop_order', 'shop_order_refund' ) ) ) {
			return;
		}

		// Retrieve customer details before the order is deleted.
		$order       = wc_get_order( $order_id );
		$customer_id = absint( CustomersDataStore::get_existing_customer_id_from_order( $order ) );

		// Delete the order.
		$wpdb->delete( self::get_db_table_name(), array( 'order_id' => $order_id ) );
		/**
		 * Fires when orders stats are deleted.
		 *
		 * @param int $order_id Order ID.
		 * @param int $customer_id Customer ID.
		 *
		 * @since 4.0.0
		 */
		do_action( 'woocommerce_analytics_delete_order_stats', $order_id, $customer_id );

		ReportsCache::invalidate();
	}


	/**
	 * Calculation methods.
	 */

	/**
	 * Get number of items sold among all orders.
	 *
	 * @param WC_Order|WC_Order_Refund $order WC_Order or WC_Order_Refund object.
	 * @return int
	 */
	protected static function get_num_items_sold( $order ) {
		$num_items = 0;

		$line_items = $order->get_items( OrderItemType::LINE_ITEM );
		foreach ( $line_items as $line_item ) {
			$num_items += $line_item->get_quantity();
		}

		return $num_items;
	}

	/**
	 * Get the net amount from an order without shipping, tax, or refunds.
	 *
	 * @param WC_Order|WC_Order_Refund $order WC_Order or WC_Order_Refund object.
	 * @return float
	 */
	protected static function get_net_total( $order ) {
		$net_total = floatval( $order->get_total() ) - floatval( $order->get_total_tax() ) - floatval( $order->get_shipping_total() );
		return (float) $net_total;
	}

	/**
	 * Whether this refund is a single lump-sum refund for the full order (e.g. status set to refunded without line items).
	 *
	 * @param WC_Order_Refund|OrderRefund|Order $refund        Refund order.
	 * @param WC_Order|Order                    $parent_order Parent order (not a refund).
	 * @return bool
	 */
	protected static function should_split_full_refund_using_parent_order( $refund, $parent_order ) {
		// The parent must be the original order, not another refund.
		if ( ! $parent_order instanceof WC_Order || 'shop_order_refund' === $parent_order->get_type() ) {
			return false;
		}

		if ( self::get_num_items_sold( $refund ) > 0 ) {
			return false;
		}

		$parent_refunds = $parent_order->get_refunds();
		if ( 1 !== count( $parent_refunds ) ) {
			return false;
		}

		$refund_total = wc_format_decimal( abs( (float) $refund->get_total() ) );
		$order_total  = wc_format_decimal( (float) $parent_order->get_total() );

		return $refund_total === $order_total;
	}

	/**
	 * Check if the wc_order_stats table has the fulfillment_status column.
	 *
	 * @return boolean
	 */
	public static function has_fulfillment_status_column() {
		$column_status = get_option( self::OPTION_ORDER_STATS_TABLE_HAS_COLUMN_ORDER_FULFILLMENT_STATUS );

		if ( ! empty( $column_status ) ) {
			return 'yes' === $column_status;
		}

		global $wpdb;

		$table_name = self::get_db_table_name();

		// Check if the table exists.
		$table_exists = $wpdb->get_var(
			$wpdb->prepare(
				// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name cannot be prepared.
				'SHOW TABLES LIKE %s',
				$table_name
			)
		);

		// If table still does not exist, return false without setting the option to allow for table to be created with the column.
		if ( ! $table_exists ) {
			return false;
		}

		$column_exists = $wpdb->get_var(
			$wpdb->prepare(
				// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name cannot be prepared.
				"SHOW COLUMNS FROM `{$table_name}` LIKE %s",
				'fulfillment_status'
			)
		);

		if ( ! empty( $column_exists ) ) {
			update_option( self::OPTION_ORDER_STATS_TABLE_HAS_COLUMN_ORDER_FULFILLMENT_STATUS, 'yes', false );
			return true;
		}

		// Update the option to indicate that the column does not exist.
		update_option( self::OPTION_ORDER_STATS_TABLE_HAS_COLUMN_ORDER_FULFILLMENT_STATUS, 'no', false );
		return false;
	}

	/**
	 * Check to see if an order's customer has made previous orders or not
	 *
	 * @param WC_Order  $order WC_Order object.
	 * @param int|false $customer_id Customer ID. Optional.
	 * @return bool
	 */
	public static function is_returning_customer( $order, $customer_id = null ) {
		if ( is_null( $customer_id ) ) {
			$customer_id = \Automattic\WooCommerce\Admin\API\Reports\Customers\DataStore::get_existing_customer_id_from_order( $order );
		}

		if ( ! $customer_id ) {
			return false;
		}

		$oldest_orders = \Automattic\WooCommerce\Admin\API\Reports\Customers\DataStore::get_oldest_orders( $customer_id );

		if ( empty( $oldest_orders ) ) {
			return false;
		}

		$first_order       = $oldest_orders[0];
		$second_order      = isset( $oldest_orders[1] ) ? $oldest_orders[1] : false;
		$excluded_statuses = self::get_excluded_report_order_statuses();

		// Order is older than previous first order.
		if ( $order->get_date_created() < wc_string_to_datetime( $first_order->date_created ) &&
			! in_array( $order->get_status(), $excluded_statuses, true )
		) {
			self::set_customer_first_order( $customer_id, $order->get_id() );
			return false;
		}

		// The current order is the oldest known order.
		$is_first_order = (int) $order->get_id() === (int) $first_order->order_id;
		// Order date has changed and next oldest is now the first order.
		$date_change = $second_order &&
			$order->get_date_created() > wc_string_to_datetime( $first_order->date_created ) &&
			wc_string_to_datetime( $second_order->date_created ) < $order->get_date_created();
		// Status has changed to an excluded status and next oldest order is now the first order.
		$status_change = $second_order &&
			in_array( $order->get_status(), $excluded_statuses, true );
		if ( $is_first_order && ( $date_change || $status_change ) ) {
			self::set_customer_first_order( $customer_id, $second_order->order_id );
			return true;
		}

		return (int) $order->get_id() !== (int) $first_order->order_id;
	}

	/**
	 * Set a customer's first order and all others to returning.
	 *
	 * @param int $customer_id Customer ID.
	 * @param int $order_id Order ID.
	 */
	protected static function set_customer_first_order( $customer_id, $order_id ) {
		global $wpdb;
		$orders_stats_table = self::get_db_table_name();

		$wpdb->query(
			$wpdb->prepare(
				'UPDATE %i SET returning_customer = CASE WHEN order_id = %d THEN false ELSE true END WHERE customer_id = %d',
				$orders_stats_table,
				$order_id,
				$customer_id
			)
		);
	}

	/**
	 * Add fulfillment_status column to wc_order_stats table.
	 *
	 * @return bool|string True on success, error message string on failure.
	 */
	public static function add_fulfillment_status_column() {
		if ( self::has_fulfillment_status_column() ) {
			return true;
		}

		global $wpdb;

		$result = $wpdb->query(
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
			"ALTER TABLE {$wpdb->prefix}wc_order_stats
			ADD COLUMN fulfillment_status VARCHAR(50) DEFAULT NULL,
			ADD INDEX fulfillment_status (fulfillment_status)"
		);

		if ( false === $result ) {
			return $wpdb->last_error ? $wpdb->last_error : __( 'Unknown database error occurred while adding fulfillment_status column.', 'woocommerce' );
		}

		// Update the option to indicate that the column has been added.
		update_option( self::OPTION_ORDER_STATS_TABLE_HAS_COLUMN_ORDER_FULFILLMENT_STATUS, 'yes', false );

		return true;
	}
}