DATE_PART
The DATE_PART() function extracts a subfield from a date value.
Syntax
DATE_PART(field,source)
Field - is a constant value that specifies the sub-field (for example, year, day, etc) to extract from the given date or timestamp.
Source - is the input date that will be processed.
Example
SELECT date_part(year,orderdate)
from
/shared/examples/ds_orders/tutorial/orders
The above query returns the year part from the orderdate column.