Added Time Conversion Functions toYYYYMM, toYYYYMMDD, and toYYYYMMDDhhmmss

Why it matters

These functions were introduced to simplify and optimize the conversion of datetime values into compact numeric representations. This is useful for efficient storage, indexing, filtering, and comparison of dates and timestamps, offering better performance and easier data manipulation for users.

How to use it

Use the functions by passing a datetime or date expression as an argument. For example:

SELECT toYYYYMM(event_date) AS year_month
FROM events

will convert event_date into a number in the YYYYMM format (e.g., 202406).

Similarly, toYYYYMMDD(datetime) returns a numeric YYYYMMDD format (e.g., 20240628), and toYYYYMMDDhhmmss(datetime) returns a numeric timestamp with year, month, day, hour, minute, second (e.g., 20240628153045).