-- 09_running: Show monthly sales and a running total
-- Read-only reference query. Setup must be loaded first.
WITH line_totals AS (
SELECT order_id,SUM(quantity*unit_price-line_discount) AS line_sales
FROM aabha_sql.order_items GROUP BY order_id
), refund_totals AS (
SELECT order_id,SUM(amount) AS refunded
FROM aabha_sql.refunds WHERE refund_date < DATE '2025-04-01' GROUP BY order_id
), order_net AS (
SELECT o.order_id,o.customer_id,o.order_date,o.channel,
l.line_sales,COALESCE(r.refunded,0) AS refunded,
l.line_sales-COALESCE(r.refunded,0) AS net_sales
FROM aabha_sql.orders AS o
JOIN line_totals AS l ON l.order_id=o.order_id
LEFT JOIN refund_totals AS r ON r.order_id=o.order_id
WHERE o.status='completed' AND o.order_date >= DATE '2025-01-01'
AND o.order_date < DATE '2025-04-01'
), monthly AS (
SELECT date_trunc('month',order_date)::date AS month,SUM(net_sales) AS net_sales
FROM order_net GROUP BY 1
)
SELECT month::text AS month,net_sales,
SUM(net_sales) OVER (ORDER BY month ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS running_sales,
LAG(net_sales) OVER (ORDER BY month) AS previous_month_sales
FROM monthly ORDER BY month;
