What is your total revenue across Amazon and Shopify — in one view?

WITH amazon_revenue AS (
  SELECT
    DATE_TRUNC('month', o.purchase_date::timestamptz)::date  AS month,
    'Amazon'                                                   AS channel,
    ROUND(SUM(i.item_price * i.quantity), 2)                 AS revenue
  FROM amazon_orders o
  JOIN amazon_order_items i ON i.amazon_order_id = o.amazon_order_id
  WHERE o.purchase_date::date >= NOW() - INTERVAL '12 months'
    AND o.order_status NOT IN ('Canceled', 'Cancelled')
  GROUP BY 1
),
shopify_revenue AS (
  SELECT
    DATE_TRUNC('month', created_at::timestamptz)::date  AS month,
    'Shopify'                                            AS channel,
    ROUND(SUM(total_price::numeric), 2)                 AS revenue
  FROM shopify_orders
  WHERE is_test_order = false
    AND cancelled_at IS NULL
    AND financial_status NOT IN ('voided','refunded')
    AND created_at::date >= NOW() - INTERVAL '12 months'
  GROUP BY 1
),
combined AS (
  SELECT * FROM amazon_revenue
  UNION ALL
  SELECT * FROM shopify_revenue
)
SELECT
  TO_CHAR(month, 'YYYY-MM')                          AS order_month,
  channel,
  revenue,
  SUM(revenue) OVER (PARTITION BY month)             AS total_revenue_all_channels
FROM combined
ORDER BY month ASC, channel