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.