Test your skills: Working with the MongoDB Aggregation Pipeline

You are using the Aggregation Editor to build a pipeline that aggregates data in the customers collection. You add the first stage and verify that the $match operator is selected. You want to filter out all documents except those with an address.state value of New York.

Which expression should you add to the editor on the Stage 1 tab?

You are using the Aggregation Editor to build a pipeline that aggregates data in the customers collection. You add a stage for grouping data based on cities in the state of New York. You want to find the total number of transactions per city.

Which accumulator operator should you use for calculating the totals?

You are using the Aggregation Editor to build a pipeline that aggregates data in the customers collection. You add a stage based on the $project operator. You want to suppress the default _id field and add a new field named ny_city. The values for the new field will come from the _id field.

You also want to include the total field in the results. Which expression should you add to the editor for this stage?

You are using the Aggregation Editor to build a pipeline that aggregates data in the customers collection. You want to add a stage to change the order of the fields in the pipeline.

Which aggregate operator should you use?