CUSTOMER (Cust#, Cname, City)
ORDER (Order#, Odate, Cust#, Ord_Amt)
ORDER_ITEM (Order#, Item#, Qty)
ITEM (Item#, Unit_price)
SHIPMENT (Order#, Warehouse#, Ship_date)
WAREHOUSE (Warehouse#, City)
Given the database model above, propose a solution for the below business requirement:
Business requirement: Assume this database belongs to an e-commerce application and the company has several warehouses in different cities. The company wants to optimize its item shipment time. You can propose a series of SQL queries. Explain your answer in details.
To optimize item shipment time for the e-commerce application, a series of SQL queries can be proposed based on the given database model. Here is a step-by-step explanation of the proposed solution:
1. Identify the warehouse with the shortest average shipment time:
We can calculate the average shipment time for each warehouse by taking the difference between the ship date and order date for each shipment. Then, we can determine the warehouse with the shortest average shipment time.
SQL Query:
```
SELECT Warehouse#, AVG(Ship_date - Odate) AS Avg_Shipment_Time
FROM SHIPMENT
GROUP BY Warehouse#
ORDER BY Avg_Shipment_Time ASC
LIMIT 1;
```
Explanation:
This query calculates the average shipment time for each warehouse by subtracting the order date (Odate) from the ship date (Ship_date). Then, it groups the results by warehouse and orders them in ascending order based on average shipment time. Finally, it selects the warehouse with the shortest average shipment time by using the LIMIT clause.
2. Find the top-selling items in the chosen warehouse:
After identifying the warehouse with the shortest average shipment time, we can determine the top-selling items in that warehouse. This can be done by retrieving the items with the highest total quantity sold.
SQL Query:
```
SELECT ITEM.Item#, ITEM.Unit_price, SUM(ORDER_ITEM.Qty) AS Total_Quantity_Sold
FROM ITEM
JOIN ORDER_ITEM ON ITEM.Item# = ORDER_ITEM.Item#
JOIN SHIPMENT ON ORDER_ITEM.Order# = SHIPMENT.Order#
WHERE SHIPMENT.Warehouse# = [chosen warehouse#]
GROUP BY ITEM.Item#
ORDER BY Total_Quantity_Sold DESC;
```
Explanation:
This query joins the ITEM, ORDER_ITEM, and SHIPMENT tables to retrieve the item number (Item#), unit price (Unit_price), and the total quantity sold (sum of Qty) for each item. It filters the results by the chosen warehouse specified in the WHERE clause. Finally, it orders the items by the total quantity sold in descending order.
3. Calculate the revenue generated by the top-selling items:
To determine the revenue generated by the top-selling items, we can multiply the total quantity sold by the unit price of each item.
SQL Query:
```
SELECT ITEM.Item#, ITEM.Unit_price, SUM(ORDER_ITEM.Qty) AS Total_Quantity_Sold, SUM(ORDER_ITEM.Qty * ITEM.Unit_price) AS Revenue
FROM ITEM
JOIN ORDER_ITEM ON ITEM.Item# = ORDER_ITEM.Item#
JOIN SHIPMENT ON ORDER_ITEM.Order# = SHIPMENT.Order#
WHERE SHIPMENT.Warehouse# = [chosen warehouse#]
GROUP BY ITEM.Item#
ORDER BY Revenue DESC;
```
Explanation:
This query is similar to the previous one but adds an additional column to calculate the revenue generated for each item. It multiplies the total quantity sold (sum of Qty) by the unit price (Unit_price) for each item. The results are then ordered by revenue in descending order.
By following these steps, the company can optimize its item shipment time by identifying the warehouse with the shortest average shipment time and focusing on the top-selling items in that warehouse to generate higher revenue.