Summarizing arrays for first, last, minimum, maximum, and average values

Financial time-series data, such as the values of currency pairs (e.g., euro-to-US dollar), fluctuates due to changing market factors. Financial institutions need rapid analytics to identify highs, lows, and averages. Even basic immediate insight such as these enable institutions to make fast, informed trading decisions, capitalizing on opportunities and avoiding potential risks. In this example, you will discover how to generate summary data for fluctuating currency-pair values.

Note

This example requires MongoDB version 4.4 or above. This is because you'll be using the $first and $last array operators, which were first introduced in version 4.4.

Scenario

You want to generate daily summaries for the exchange rates of foreign currency pairs. You need to analyze an array of persisted hourly rates for each currency pair for each day. You will output a daily summary of the open (first), close (last...