$sum

The $sum aggregation operator calculates the total sum of numeric values across grouped documents or array elements. It's commonly used with $group to aggregate numeric data, create totals, and perform mathematical operations in aggregation pipelines. $sum ignores non-numeric values and can sum field values, literal numbers, or results from expressions, making it essential for financial and statistical calculations.

Visit the following resources to learn more:

• @official@$sum
• @official@Aggregation Operators