Fixed Challenge heading

Author: sourabhbagrecha

docs/50-aggregation/3-sort-limit.mdx

@@ -1,3 +1,6 @@
+import Tabs from "@theme/Tabs";
+import TabItem from "@theme/TabItem";
+
 # 👐 $sort and $limit
 
 ## 🔹 $sort → Sorting results
@@ -67,24 +70,54 @@ SELECT * FROM books ORDER BY timestamp DESC LIMIT 5;
 
 ---
 
-### 👐 Challenge
+## 👐 Challenge
 
 ## 👐 1. After the year 2010, which book has the most number of authors?
 
 <details>
   <summary>Answer</summary>
   <div>
-    ```js
+  There are 2 ways to solve this- 
+  - $project
+  - $addFields
+
+:::info
+Learn [when to use $addFields over $project](https://www.practical-mongodb-aggregations.com/guides/project.html?highlight=%24project#when-to-use-project)
+:::
+
+  <Tabs groupId="aggregations">
+    <TabItem value="mongodb-shell" label="Using $project">
+      ```js
       db.books.aggregate([
+          {
+            $match: { year: {$gt: 2010}}
+          },
+          {
+            $project: {
+              title: 1,
+              authors: 1,
+              numAuthors: {$size: "$authors"},
+              _id: 0
+            }
+          },
+          {
+            $sort: { "numAuthors": -1}
+          },
+          {
+            $limit: 1
+          }
+        ]);
+      ```
+    </TabItem>
+    <TabItem value="atlas" label="Using $addFields">
+    ```js
+    db.books.aggregate([
         {
           $match: { year: {$gt: 2010}}
         },
         {
-          $project: {
-            title: 1,
-            authors: 1,
+          $addFields: {
             numAuthors: {$size: "$authors"},
-            _id: 0
           }
         },
         {
@@ -95,5 +128,7 @@ SELECT * FROM books ORDER BY timestamp DESC LIMIT 5;
         }
       ]);
     ```
+    </TabItem>
+  </Tabs>
   </div>
 </details>

docs/50-aggregation/4-group.mdx

@@ -152,6 +152,7 @@ GROUP BY year;
 
 <details>
   <summary>Answer</summary>
+  <div>
   There are 2 ways to solve this- 
   - $group with $sort 
   - $sortByCount
@@ -185,4 +186,5 @@ GROUP BY year;
     </TabItem>
 
   </Tabs>
+  </div>
 </details>

docs/50-aggregation/7-CREATE-VIEW.mdx

@@ -72,26 +72,13 @@ ON DUPLICATE KEY UPDATE totalBooks = VALUES(totalBooks);
 
 ---
 
-## **🔹 Example 2: Maintaining an author summary table**
+## 👐 Challenge
 
-👉 We want to create an **author_stats** collection with the total number of books written by each author.
+### **🔹 1: Maintaining an Author Summary Table**
 
-```js
-db.books.aggregate([
-  { $unwind: "$authors" },
-  { $group: { _id: "$authors.name", totalBooks: { $sum: 1 } } },
-  {
-    $merge: {
-      into: "author_stats",
-      on: "_id",
-      whenMatched: "merge",
-      whenNotMatched: "insert",
-    },
-  },
-]);
-```
+👉 We want to create an **author_stats** collection with the total number of books written by each author.
 
-### **SQL equivalent**
+### Hint: SQL equivalent
 
 ```sql
 INSERT INTO author_stats (authorName, totalBooks)
@@ -100,25 +87,20 @@ GROUP BY authors.name
 ON DUPLICATE KEY UPDATE totalBooks = VALUES(totalBooks);
 ```
 
----
-
-## 👐 Challenge
-
-👐 Create a `top_rated_books` collection that stores books with an average rating above 4.5.
-
 <details>
   <summary>Answer</summary>
-    ```js
+  ```js
     db.books.aggregate([
+      { $unwind: "$authors" },
+      { $group: { _id: "$authors.name", totalBooks: { $sum: 1 } } },
       {
-        $lookup:
-          {
-            from: "reviews",
-            localField: "_id",
-            foreignField: "bookId",
-            as: "reviews"
-          }
-      }
+        $merge: {
+          into: "author_stats",
+          on: "_id",
+          whenMatched: "merge",
+          whenNotMatched: "insert",
+        },
+      },
     ]);
     ```
 </details>