Count documents satisfying a query in MongoDB Collection (countDocuments, $regex, $in)

In this lesson, we learn that counting documents that meet certain criteria in MongoDB can be done with the countDocuments() method.

We demonstrate how to retrieve the total number of documents when no query is specified and how to filter results using regular expressions.

For example, we can count employees with names containing a lowercase "a" or those with specific skills, using $regex.

Additionally, we show how to count documents where age is not equal to a given value, illustrating the versatility of the countDocuments() method in various scenarios.