Which function would you use to round datetime expressions?

The function that is used to round datetime expressions is TIMEBUCKET. This function allows users to group timestamps into specified intervals, effectively rounding the datetime to the nearest bucketed time. For instance, if you need to analyze data at hourly intervals or in 15-minute blocks, TIMEBUCKET can simplify the data into these intervals, making it easier to analyze trends over specified time periods.

While other functions have specific uses, such as extracting time values (TIMEVALUE) or manipulating strings (TRIM and MID), they do not serve the purpose of rounding datetime values. Thus, TIMEBUCKET stands out as the appropriate choice for managing datetime expressions effectively.