Changes between Initial Version and Version 1 of AdvancedReport2

Timestamp:

08/21/26 05:27:15 (30 hours ago)

Author:

235018

Comment:

--

AdvancedReport2

@@ +1 @@
+= List of most popular products with total number of sales
+{{{#!sql
+CREATE OR REPLACE FUNCTION get_products_by_total_sales()
+RETURNS TABLE (
+    product_code INT,
+    product_description TEXT,
+    product_price NUMERIC,
+    number_of_orders BIGINT,
+    total_revenue NUMERIC
+)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    RETURN QUERY
+    SELECT
+        p.code AS product_code,
+        p.description AS product_description,
+        p.price AS product_price,
+        COUNT(DISTINCT o.order_num) AS number_of_orders,
+        COALESCE(
+            SUM(
+                p.price
+                * o.quantity
+                * (1 - COALESCE(o.discount, 0) / 100.0)
+            ),
+            0
+        ) AS total_revenue
+    FROM product p
+    LEFT JOIN includes i
+        ON p.code = i.code
+    LEFT JOIN "order" o
+        ON i.order_num = o.order_num
+    GROUP BY
+        p.code,
+        p.description,
+        p.price
+    ORDER BY
+        number_of_orders DESC,
+        total_revenue DESC;
+END;
+$$;
+
+}}}
+
+== Relational Algebra
+- P(code, price, availability, description, ...)
+- O(order_num, quantity, status, last_modified_date, payment_method, discount)
+- I(code, order_num)
+
+**JOIN products with orders:**
+- J1 ← P ⟕P.code = I.code I
+- J2 ← J1 ⟕I.order_num = O.order_num O
+
+**Calculate revenue from product for each order:**
+- **FORMULA:** order_total = Σ(P.price × O.quantity) × (1 - COALESCE(O.discount, 0) / 100)
+
+- OR ← πcode, description, price, order_num, quantity, discount,
+      price × quantity ×
+      (1 - COALESCE(discount, 0) / 100)
+      → order_revenue(J2)
+
+* OR = order revenue
+
+**Calculate total number of orders the product has been in and total revenue:**
+- R ← γcode, description, price;
+     COUNT(DISTINCT order_num) → number_of_orders,
+     Σ(order_revenue) → total_revenue
+     (OR)
+- For products that have never been ordered:
+    - number_of_orders = 0
+    - total_revenue = 0
+
+**Sort by order total:**
+- R_final ← τnumber_of_orders DESC, total_revenue DESC(R)
+
+