SQL
Date Part Extraction Functions
There are also dedicated extraction functions to get the [subfields](#docs:sql:functions:datepart::part-functions).
A few examples include extracting the day from a date, or the day of the week from a date.  
Functions applied to infinite dates will either return the same infinite dates
(e.g, `greatest`) or `NULL` (e.g., `date_part`) depending on what “makes sense”.
In general, if the function needs to examine the parts of the infinite date, the result will be `NULL`.