# MongoDB Operators

MongoDB provides various query operators that allow you to perform complex queries and filtering operations on your data.

#### OR Operator (`$or`)

The `$or` operator allows you to perform a logical OR operation on an array of query expressions. It returns documents that match at least one of the specified expressions.

```
db.collectionName.find({
  $or: [
    {category: "books"},
    {category: "electronics"},
    {price: {$gt: 50}}
  ]
})
```

This query will return documents where the category is either "books" or "electronics", or where the price is greater than 50.

#### NOR Operator (`$nor`)

The `$nor` operator is the logical complement of the `$or` operator. It returns documents that do not match any of the specified expressions.

```
db.collectionName.find({
  $nor: [
    {category: "books"},
    {category: "electronics"},
    {price: {$gt: 50}}
  ]
})
```

This query will return documents where the category is neither "books" nor "electronics", and the price is not greater than 50.

#### NOT Operator (`$not`)

The `$not` operator is used to negate the result of a query expression. It returns documents that do not match the specified expression.

```
db.collectionName.find({
  name: {$not: /^A/}
})
```

This query will return documents where the name field does not start with the letter "A".

#### Limiting and Skipping Documents

You can limit the number of documents returned by a query using the `limit()` method:

```
db.collectionName.find().limit(5)
```

This will return only the first 5 documents from the result set.

To skip a specified number of documents, use the `skip()` method:

```
db.collectionName.find().skip(10).limit(5)
```

This will skip the first 10 documents and return the next 5 documents from the result set.