The DAY function returns the day part of a value.
The argument must be a date, timestamp, or a valid character
string representation of a date or timestamp that is not a CLOB, LONG VARCHAR,
or XML value. The result of the function is a large integer. If the argument
can be null, the result can be null; if the argument is null, the result is
the null value.
The other rules depend on the data type of the argument
- If the argument is a date, timestamp, or valid string representation of
a date or timestamp: The result is the day part of the value, which is an
integer between 1 and 31.
- If the argument is a time duration or timestamp duration: The result is
the day part of the value, which is an integer between -99 and 99. A nonzero
result has the same sign as the argument.
DAY ( expression )
value is 2.