Added unset

Author: dfreniche

docs/80-modifying-results/adding-fields.mdx

@@ -1,3 +1,7 @@
+---
+sidebar_position: 10
+---
+
 import Tabs from '@theme/Tabs';
 import TabItem from '@theme/TabItem';
 

docs/80-modifying-results/unset-fields.mdx

@@ -0,0 +1,91 @@
+---
+sidebar_position: 20
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# 👐 Unset Fields from Results
+
+## $unset
+
+We can remove fields from the results, either using $project or more fine-grained, using $unset. If we don't want the attributes we can do:
+
+
+<Tabs groupId="aggregations">
+<TabItem value="atlas" label="Atlas UI">
+
+```js
+[
+    {$unset: "attributes"}
+]
+```
+
+</TabItem>
+
+<TabItem value="mongodb-shell" label="MongoDB Shell">
+
+```js
+db.books.aggregate([
+      {$unset: "attributes"}
+])
+```
+
+</TabItem>
+</Tabs>
+
+
+👐 Remove from results the fields `totalInventory` and `available`.
+
+<details>
+<summary>Answer</summary>
+<div>
+
+<Tabs groupId="aggregations">
+<TabItem value="atlas" label="Atlas UI">
+
+Several ways to do this, other than using `$project`:
+
+```js
+[
+    {$unset: "totalInventory"},
+    {$unset: "available"},
+]
+
+// or
+
+[
+    {$unset: ["totalInventory", "available"] },
+]
+```
+
+</TabItem>
+
+<TabItem value="mongodb-shell" label="MongoDB Shell">
+
+```js
+db.books.aggregate([
+    {$unset: "totalInventory"},
+    {$unset: "available"},
+])
+
+// or
+
+db.books.aggregate([
+    {$unset: ["totalInventory", "available"] },
+])
+
+```
+
+</TabItem>
+</Tabs>
+
+
+
+</div>
+
+:::info
+[$set](https://www.mongodb.com/docs/manual/reference/operator/aggregation/set/#mongodb-pipeline-pipe.-set) is an alias for $addFields that you'll find on many older posts and documentation.
+:::
+
+</details>