Improve queries

src/data/courses/sql-mastery/chapters/subqueries-and-ctes/lessons/books-above-average.md

@@ -43,7 +43,7 @@ Write a query that shows:
 - Price
 - How much the price is above the average (rounded to 2 decimal places)
 
-Only include books that are priced above the average book price.
+Only include books that are priced above the average book price and order by price in descending order.
 
 ## Expected Output
 

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

@@ -67,6 +67,5 @@ WHERE b1.published_date = (
     SELECT MAX(published_date)
     FROM book b2
     WHERE b2.category = b1.category
-)
+);
-ORDER BY b1.category;
 ``` 

src/data/courses/sql-mastery/chapters/subqueries-and-ctes/lessons/low-stock-by-category.md

@@ -75,18 +75,5 @@ WHERE b1.stock < (
     SELECT AVG(stock)
     FROM book b2
     WHERE b2.category = b1.category
-)
+);
-ORDER BY b1.category, b1.stock;
 ```
-
-This challenge requires you to:
-1. Use a correlated subquery to calculate the average stock for each category
-2. Compare each book's stock to its category average
-3. Show only books with below-average stock
-
-The solution demonstrates:
-- Using correlated subqueries in both SELECT and WHERE clauses
-- Comparing individual values against group averages
-- Working with a single table
-
----

src/data/courses/sql-mastery/chapters/subqueries-and-ctes/lessons/new-customer-analysis.md

@@ -90,6 +90,8 @@ Write a query using CTEs that shows the top 3 selling books and how many new cus
 - Total quantity sold
 - Number of new customers who bought the book
 
+Order by total quantity sold in descending order.
+
 ## Expected Output
 
 | title        | total_sold | new_customer_count |