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Update 2-match-project.mdx #9

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16 changes: 8 additions & 8 deletions docs/50-aggregation/2-match-project.mdx
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# 👐 $match and $project

MongoDB’s **Aggregation Framework** allows for powerful data transformations and analysis. The **$match**, **$project** & **$sort** stages are fundamental building blocks of an aggregation pipeline.
MongoDB’s **Aggregation Framework** allows for powerful data transformations and analysis. The **$match**, **$project**, and **$sort** stages are fundamental building blocks of an aggregation pipeline.

---

## **🔹 $match → Filtering Data**
## **🔹 $match → Filtering data**

Just like `.find()` based on the query mentioned, the `$match` stage filters documents from the collection.

Expand All @@ -14,7 +14,7 @@ Just like `.find()` based on the query mentioned, the `$match` stage filters doc
{ $match: { <query> } }
```

### Example: Get All the Books that were published after the year 2010
### Example: Get all the books that were published after the year 2010

```js
db.books.aggregate([
Expand All @@ -30,7 +30,7 @@ Place `$match` as early as possible in the pipeline to reduce the number of docu

---

## **🔹 $project → Selecting Fields**
## **🔹 $project → Selecting fields**

- The `$project` stage controls which fields are included in the output.
- It can also be used for adding computed fields to the results.
Expand All @@ -50,7 +50,7 @@ Place `$match` as early as possible in the pipeline to reduce the number of docu
- `1`: Include the field
- `0`: Exclude the field

### Example: Get all the books published after the year 2010, the output should only include the title, year and page count of the book.
### Example: Get all the books published after the year 2010. The output should only include the title, year, and page count of the book.

```js
db.books.aggregate([
Expand All @@ -68,13 +68,13 @@ db.books.aggregate([
]);
```

### **Equivalent SQL Query**
### **Equivalent SQL query**

```sql
SELECT title, year, pages FROM books WHERE year>2010;
```

### **Computed Fields Example:** Along with the title & authors, also output the count of authors for every book in the database.
### **Computed fields example:** Along with the title and authors, also output the count of authors for every book in the database.

```js
db.books.aggregate([
Expand Down Expand Up @@ -105,7 +105,7 @@ db.books.aggregate([
</div>
</details>

### 👐 2. Find books with more than 2 available copies, return only book titles and publication year.
### 👐 2. Find books with more than 2 available copies. Return only book titles and publication year.

<details>
<summary>Answer</summary>
Expand Down