Getting further help

This book does not aim to document every possible option and parameter for the stages and operators that can constitute a MongoDB aggregation pipeline. That's what the MongoDB online documentation is for. Specifically, you should consult the following for help on the syntax of aggregation stages and operators:

• MongoDB aggregation pipeline stages (see https://docs.mongodb.com/manual/reference/operator/aggregation-pipeline/)
• MongoDB aggregation pipeline operators (see https://www.mongodb.com/docs/manual/reference/operator/aggregation/)

If you are getting stuck with an aggregation pipeline and want some help, an active online community will almost always have the answer. So, pose your questions here:

• The MongoDB Community Forums (see https://www.mongodb.com/community/forums/)
• Stack Overflow – MongoDB Questions (see https://stackoverflow.com/questions/tagged/mongodb)

You may be asking for just general advice. However, suppose you want to ask for help on a specific aggregation pipeline under development. In that case, you should provide a sample input document, a copy of your current pipeline code (in its JSON syntax format and not a programming language-specific format), and an example of the output that you are trying to achieve. If you provide this extra information, you will have a far greater chance of receiving a timely and optimal response.