Extraction (extraction_function) 
An extraction (extraction_function) is a function that extracts parts of a date, time or time stamp value or that calculates a date, time or time stamp value.
Structure
Syntax
<extraction_function> ::= DATE(<expression>) | DAY(<date_or_timestamp_expression>) | HOUR(<time_or_timestamp_expression>) | MICROSECOND(<expression>) | MINUTE(<time_or_timestamp_expression>) | MONTH(<date_or_timestamp_expression>) | SECOND(<time_or_timestamp_expression>) | TIME(<expression>) | TIMESTAMP(<expression>[,<expression>]) | YEAR(<date_or_timestamp_expression>) <date_or_timestamp_expression ::= <expression> <time_or_timestamp_expression> ::= <expression>
End of the code.
Examples
SQL Tutorial, Date and Time Calculations
Explanation
When used in a function, the argument date_or_timestamp_expression must supply a date, time stamp or alphanumeric value that matches the current date or time stamp format. When used in a function, the argument time_or_timestamp_expression must supply a time, time stamp or alphanumeric value that matches the current time or time stamp format. Date and time values are available in a variety of date and time formats (ISO, USA, EUR, JIS, INTERNAL)