Add latest category books challenge

src/data/courses/sql-mastery/chapters/subqueries-and-ctes/lessons/latest-category-books.md

@@ -0,0 +1,72 @@
+---
+title: Latest Category Books
+description: Practice using correlated subqueries to find the most recent books in each category
+order: 141
+type: challenge
+setup: |
+  ```sql
+  CREATE TABLE book (
+      id INT PRIMARY KEY,
+      title VARCHAR(100),
+      category VARCHAR(50),
+      published_date DATE,
+      price DECIMAL(10,2)
+  );
+
+  INSERT INTO book (id, title, category, published_date, price) VALUES
+      (1, 'SQL Basics', 'Programming', '2023-06-15', 29.99),
+      (2, 'Advanced SQL', 'Programming', '2024-01-20', 49.99),
+      (3, 'Data Science', 'Data Analysis', '2023-12-10', 39.99),
+      (4, 'Web Development', 'Programming', '2023-09-01', 34.99),
+      (5, 'Statistics 101', 'Data Analysis', '2024-02-15', 24.99),
+      (6, 'Machine Learning', 'Data Analysis', '2023-11-15', 44.99),
+      (7, 'Python Basics', 'Programming', '2024-02-01', 29.99),
+      (8, 'R Programming', 'Data Analysis', '2024-01-05', 34.99);
+  ```
+---
+
+The bookstore wants to highlight the most recently published book in each category. This will help them promote their newest offerings to customers.
+
+Given the following data in table `book`:
+
+| id  | title           | category      | published_date | price |
+| --- | --------------- | ------------- | -------------- | ----- |
+| 1   | SQL Basics      | Programming   | 2023-06-15    | 29.99 |
+| 2   | Advanced SQL    | Programming   | 2024-01-20    | 49.99 |
+| 3   | Data Science    | Data Analysis | 2023-12-10    | 39.99 |
+| 4   | Web Development | Programming   | 2023-09-01    | 34.99 |
+| 5   | Statistics 101  | Data Analysis | 2024-02-15    | 24.99 |
+| 6   | Machine Learning| Data Analysis | 2023-11-15    | 44.99 |
+| 7   | Python Basics   | Programming   | 2024-02-01    | 29.99 |
+| 8   | R Programming   | Data Analysis | 2024-01-05    | 34.99 |
+
+Write a query that finds the most recently published book in each category. The query should show:
+
+- Category
+- Book title
+- Published date
+- Price
+
+## Expected Output
+
+| category      | title          | published_date | price |
+| ------------- | -------------- | -------------- | ----- |
+| Data Analysis | Statistics 101 | 2024-02-15    | 24.99 |
+| Programming   | Python Basics  | 2024-02-01    | 29.99 |
+
+## Solution
+
+```sql
+SELECT 
+    b1.category,
+    b1.title,
+    b1.published_date,
+    b1.price
+FROM book b1
+WHERE b1.published_date = (
+    SELECT MAX(published_date)
+    FROM book b2
+    WHERE b2.category = b1.category
+)
+ORDER BY b1.category;
+```