Harnessing the Power of Expressions
In this chapter, you will learn about the different types of aggregation expressions, how to combine them, and how they can help you enhance your aggregation pipelines. Using nested expressions can be highly effective for solving complex problems, particularly those involving arrays. Since nesting introduces added complexity, this chapter devotes significant attention to guiding you through the intricacies of crafting composite expressions for array processing.
To summarize, you will learn the following key concepts in this chapter:
- Types of aggregation expressions
- How to chain expressions together
- The power array operators
- Conditional comparisons
- Techniques for looping through and processing array elements
Let's begin by exploring the various types of aggregation expressions.