Added date_trunc Function for Date/Time Truncation

Why it matters

The date_trunc function solves the need to truncate date and time values to a specific component, such as year, month, day, hour, etc. This enables users to perform more precise grouping or filtering operations by standardized date/time intervals, improving query accuracy and flexibility in time series analysis.

How to use it

Use the date_trunc function by specifying the date/time part to which you want to truncate and the date/time value. For example:

SELECT date_trunc('month', <timestamp_column>) FROM <table>

This will truncate the timestamps to the first day of their respective months.