Unraveling the Complexity: Mastering SQL Assignments with Expert Guidance

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thomamss 03 Feb 2024

Explore the intricacies of SQL with our expert's solution to the challenging query: finding the second-highest salary in each department. Need help with SQL assignments? We've got you covered!

Greetings, coding enthusiasts! Today, we delve into the intricate world of SQL assignments, exploring a challenging question that often leaves students scratching their heads. Whether you're a programming novice or a seasoned coder, mastering SQL requires a deep understanding of its nuances. To help you navigate through the complexities, our expert at ProgrammingHomeworkHelp.com is here to unravel the secrets behind a particularly tricky SQL assignment.

Question:

Consider a database schema with two tables: Orders and OrderDetails. The Orders table has columns (OrderID, CustomerID, OrderDate), and the OrderDetails table has columns (OrderID, ProductID, Quantity, Price). Write an SQL query to find the total revenue generated by each customer in the year 2023. Display the result in descending order of total revenue.

Note:

Assume that the OrderDate column is in the format 'YYYY-MM-DD'.
Total revenue for each customer is the sum of the product of quantity and price for all the products they ordered.

This question assesses your ability to work with multiple tables, perform aggregations, and filter data based on specific criteria.

Solution:

To find the total revenue generated by each customer in the year 2023, you can use the following SQL query:

SELECT
o.CustomerID,
SUM(od.Quantity * od.Price) AS TotalRevenue
FROM
Orders o
JOIN
OrderDetails od ON o.OrderID = od.OrderID
WHERE
YEAR(o.OrderDate) = 2023
GROUP BY
o.CustomerID
ORDER BY
TotalRevenue DESC;

Explanation:

SELECT Statement: It selects the columns that you want in the final result - CustomerID and the calculated total revenue.
FROM Clause: It specifies the tables used in the query. In this case, it's joining the Orders table (o) with the OrderDetails table (od) based on the common column OrderID.
WHERE Clause: It filters the data to include only records from the year 2023.
GROUP BY Clause: It groups the results by CustomerID so that the sum of revenue is calculated for each customer separately.
SUM Function: It calculates the total revenue for each customer by multiplying the Quantity and Price for each product and then summing up these values.
ORDER BY Clause: It orders the result set in descending order based on the calculated TotalRevenue.