What is the method for reducing the number of records by summarizing groups of records within a dataset?

The method used to reduce the number of records by summarizing groups of records within a dataset is through a "Group by" operation. This concept allows users to aggregate data based on specific fields or attributes, effectively condensing multiple records into a single summary record for each group. For example, if you have sales data divided by region and want to get the total sales for each region, using a "Group by" operation enables you to calculate the total while only displaying one row per region.

This method is particularly useful for analysis, as it simplifies datasets by presenting summarized information, making it easier to identify trends or insights without being overwhelmed by excessive data points. Other operations available in data manipulation, such as filtering or joining, serve different functions. Filtering is used to limit records based on certain criteria without summarization, joining combines datasets based on relationships, and unpivoting transforms columns into rows rather than summarizing data.