Which function is considered an aggregating function in SQL?

An aggregating function in SQL is designed to perform a calculation on a set of values and return a single value as a result. The MIN function is used to determine the smallest value in a specified column or expression, effectively summarizing data by providing an overall minimum value across a dataset. This characteristic of collapsing a set of values into a single result is what qualifies MIN as an aggregating function.

In contrast, functions like TRIM and REPLACE are not aggregating functions; they manipulate string data but do not summarize data across multiple rows. TRIM removes spaces from both ends of a string, while REPLACE substitutes specified characters with others within strings. Similarly, SUBSTRING retrieves a portion of a string based on specified parameters but does not aggregate data from multiple rows. Therefore, MIN appropriately aligns with the definition of an aggregating function, which focuses on summarizing or performing calculations over a collection of data.