Этап: Аналитические запросы

sql/daily_revenue.sql

@@ -0,0 +1,16 @@
+WITH RECURSIVE calendar(day, last_day) AS (
+    SELECT MIN(order_date), MAX(order_date) FROM daily_category_revenue
+    HAVING COUNT(*) > 0
+    UNION ALL
+    SELECT date(day, '+1 day'), last_day FROM calendar WHERE day < last_day
+),
+daily AS (
+    SELECT day AS order_date, COALESCE(SUM(r.revenue_kopecks), 0) AS revenue_kopecks
+    FROM calendar
+    LEFT JOIN daily_category_revenue AS r ON r.order_date = day
+    GROUP BY day
+)
+SELECT order_date, revenue_kopecks,
+       revenue_kopecks - LAG(revenue_kopecks) OVER (ORDER BY order_date) AS change_kopecks
+FROM daily
+ORDER BY order_date;