Add lesson about limit and offset

src/data/courses/sql/chapters/sql-basics/lessons/limiting-results-with-limit.md

@@ -0,0 +1,125 @@
+---
+title: Limiting Results with LIMIT
+description: Learn how to limit the results of a query.
+order: 160
+type: lesson-challenge
+---
+
+Real-world data is often large and complex, and it's not always practical to return all the data in a single query. SQL offers a way to limit the number of rows returned by a query using `LIMIT` clause.
+
+For example, given the following `orders` table:
+
+| id | customer_id | order_date | total |
+|----|-------------|------------|-------|
+| 1  | 101         | 2024-01-01 | 100   |
+| 2  | 102         | 2024-01-02 | 200   |
+| 3  | 103         | 2024-01-03 | 300   |
+| 4  | 104         | 2024-01-04 | 400   |
+| 5  | 105         | 2024-01-05 | 500   |
+
+If we want to get the first 2 rows from the `orders` table, we can use the following SQL query:
+
+```sql
+SELECT *
+FROM orders
+LIMIT 2;
+```
+
+The output of this query will be:
+
+| id | customer_id | order_date | total |
+|----|-------------|------------|-------|
+| 1  | 101         | 2024-01-01 | 100   |
+| 2  | 102         | 2024-01-02 | 200   |
+
+## Limiting with Filter and Order
+
+If you use `LIMIT` in a `SELECT` statement with a `WHERE` clause and an `ORDER BY` clause, the `LIMIT` clause is executed after the `WHERE` clause and the `ORDER BY` clause.
+
+
+### Any 2 orders with order amount > 200
+
+For example, if we want to get the 2 orders with the order amount greater than 200, we can use the following SQL query:
+
+```sql
+SELECT *
+FROM orders
+WHERE total > 200
+LIMIT 2;
+```
+
+Since we don't have sorting applied, the output may contain **any 2 orders** with the order amount greater than 200.
+
+| id | customer_id | order_date | total |
+|----|-------------|------------|-------|
+| 3  | 103         | 2024-01-03 | 300   |
+| 4  | 104         | 2024-01-04 | 400   |
+
+### 2 most expensive orders with order amount > 200
+
+If we want to get the 2 most expensive orders with the order amount greater than 200, we can use the following SQL query:
+
+```sql
+SELECT *
+FROM orders
+WHERE total > 200
+ORDER BY total DESC
+LIMIT 2;
+```
+
+The output of this query will be:
+
+| id | customer_id | order_date | total |
+|----|-------------|------------|-------|
+| 5  | 105         | 2024-01-05 | 500   |
+| 4  | 104         | 2024-01-04 | 400   |
+
+As you can see, the output contains the **2 most expensive orders** with the order amount greater than 200.  This tells us that the `LIMIT` clause is executed in the following order:
+
+1. `WHERE` clause - filters the orders with the order amount greater than 200
+2. `ORDER BY` clause - sorts the orders by the order amount in descending order
+3. `LIMIT` clause - limits the number of rows returned to 2
+
+## Excluding rows with OFFSET
+
+If you want to exclude a certain number of rows from the result, you can use the `OFFSET` clause. `OFFSET x` is used to skip the first `x` rows from the result set and it **must be used in conjunction with the `LIMIT` clause**.
+
+For example, if we want to get the 2 most expensive orders with the order amount greater than 200, our query will be:
+
+```sql
+SELECT *
+FROM orders
+WHERE total > 200
+ORDER BY total DESC
+LIMIT 2 
+OFFSET 1;
+```
+
+The output of this query will be:
+
+| id | customer_id | order_date | total |
+|----|-------------|------------|-------|
+| 4  | 104         | 2024-01-04 | 400   |
+| 3  | 103         | 2024-01-03 | 300   |
+
+As you can see, because of `OFFSET 1`, it did not return the most expensive order (i.e., the order with a total of 500) and instead returned the second and third most expensive orders (i.e., the order with a total of 400 and 300). This tells us that the `OFFSET` clause is executed after the `WHERE` clause and the `ORDER BY` clause.
+
+---
+
+## Challenge
+
+Given the following `orders` table, write a query to get the cheapest 1 order.
+
+| id | customer_id | order_date | total |
+|----|-------------|------------|-------|
+| 2  | 102         | 2024-01-02 | 200   |
+| 3  | 103         | 2024-01-03 | 300   |
+| 1  | 101         | 2024-01-01 | 100   |
+| 4  | 104         | 2024-01-04 | 400   |
+| 5  | 105         | 2024-01-05 | 500   |
+
+Your query should return the following result:
+
+| id | customer_id | order_date | total |
+|----|-------------|------------|-------|
+| 1  | 101         | 2024-01-01 | 100   |

src/data/courses/sql/chapters/sql-basics/lessons/sorting-results.md

@@ -0,0 +1,94 @@
+---
+title: Sorting with ORDER BY
+description: Learn how to sort the results of a query.
+order: 140
+type: lesson-challenge
+---
+
+We can use the `ORDER BY` clause to sort the results of a query. Taking the example of the `orders` table from the previous lesson:
+
+| id  | customer_id | total_amount | order_date |
+| --- | ----------- | ------------ | ---------- |
+| 1   | 1           | 100          | 2024-01-01 |
+| 2   | 2           | 200          | 2024-01-02 |
+| 3   | 3           | 150          | 2024-01-03 |
+| 4   | 4           | 300          | 2024-01-04 |
+| 5   | 5           | 250          | 2024-01-05 |
+
+If we want to get all the orders sorted by the `total_amount` column in descending order i.e. the highest total amount first, we can use the following SQL query:
+
+```sql
+SELECT *
+FROM orders
+ORDER BY total_amount DESC;
+```
+
+The output of this query would be:
+
+| id  | customer_id | total_amount | order_date |
+| --- | ----------- | ------------ | ---------- |
+| 4   | 4           | 300          | 2024-01-04 |
+| 5   | 5           | 250          | 2024-01-05 |
+| 3   | 3           | 150          | 2024-01-03 |
+| 2   | 2           | 200          | 2024-01-02 |
+| 1   | 1           | 100          | 2024-01-01 |
+
+Similarly, to get the orders sorted in ascending order by the `total_amount` column, we can use the following SQL query:
+
+```sql
+SELECT *
+FROM orders
+ORDER BY total_amount ASC;
+```
+
+## Sorting by Multiple Columns
+
+We can also sort the results by multiple columns. This is useful when we want to sort the results by one column and then sort them by another column if the first column values are identical.
+
+For example, let's say we have a table called `books` that contains information about books in our store:
+
+| id  | title                  | author              | price | stock |
+| --- | ---------------------- | ------------------- | ----- | ----- |
+| 1   | The Great Gatsby       | F. Scott Fitzgerald | 15.99 | 5     |
+| 2   | To Kill a Mockingbird  | Harper Lee          | 15.99 | 8     |
+| 3   | 1984                   | George Orwell       | 12.99 | 3     |
+| 4   | Pride and Prejudice    | Jane Austen         | 15.99 | 2     |
+| 5   | The Catcher in the Rye | J.D. Salinger       | 12.99 | 6     |
+
+To sort the books first by price (highest first) and then by stock quantity (lowest first) for books with the same price, we can use the following SQL query:
+
+```sql
+SELECT *
+FROM books
+ORDER BY price DESC, stock ASC;
+```
+
+The output of this query would be:
+
+| id  | title                  | author              | price | stock |
+| --- | ---------------------- | ------------------- | ----- | ----- |
+| 4   | Pride and Prejudice    | Jane Austen         | 15.99 | 2     |
+| 1   | The Great Gatsby       | F. Scott Fitzgerald | 15.99 | 5     |
+| 2   | To Kill a Mockingbird  | Harper Lee          | 15.99 | 8     |
+| 3   | 1984                   | George Orwell       | 12.99 | 3     |
+| 5   | The Catcher in the Rye | J.D. Salinger       | 12.99 | 6     |
+
+Notice the highest-priced books at the top; books with IDs `1`, `2`, and `4` have the same price, but the book with ID `4` has less stock than the books with IDs `1` and `2`, so it comes first.
+
+If we want to sort the books first by price (highest first) and then by stock quantity (highest first) for books with the same price, we can use the following SQL query:
+
+```sql
+SELECT *
+FROM books
+ORDER BY price DESC, stock DESC;
+```
+
+The output of this query would be:
+
+| id  | title                  | author              | price | stock |
+| --- | ---------------------- | ------------------- | ----- | ----- |
+| 2   | To Kill a Mockingbird  | Harper Lee          | 15.99 | 8     |
+| 1   | The Great Gatsby       | F. Scott Fitzgerald | 15.99 | 5     |
+| 4   | Pride and Prejudice    | Jane Austen         | 15.99 | 2     |
+| 5   | The Catcher in the Rye | J.D. Salinger       | 12.99 | 6     |
+| 3   | 1984                   | George Orwell       | 12.99 | 3     |

src/styles/global.css

@@ -56,6 +56,9 @@ h3 > code {
 .prose ul li > code:before,
 p > code:before,
 .prose ul li > code:after,
+.prose ol li > code:before,
+p > code:before,
+.prose ol li > code:after,
 p > code:after,
 a > code:after,
 a > code:before {