MongoDB is a source-available cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and licensed under the Server Side Public License (SSPL) which is deemed non-free by several distributions. MongoDB is a member of the MACH Alliance.
Source: Wikipedia
Running Queries against MongoDB
The following operation returns all the documents from the products collection where qty is greater than 25 and returns only the _id, item and qty fields:
db.products.find( { qty: { $gt: 25 } }, { item: 1, qty: 1 } )