Sure it does:
Native aggregates
Count
The count function can be used to count the rows returned by a query.
Example:
SELECT COUNT (*) FROM plays;
SELECT COUNT (1) FROM plays;
It also can be used to count the non null value of a given column:
SELECT COUNT (scores) FROM plays;
Max and Min
The max and min functions can be used to compute the maximum and the
minimum value returned by a query for a given column. For instance:
SELECT MIN (players), MAX (players) FROM plays WHERE game = 'quake';
Sum
The sum function can be used to sum up all the values returned by a
query for a given column. For instance:
SELECT SUM (players) FROM plays;
Avg
The avg function can be used to compute the average of all the values
returned by a query for a given column. For instance:
SELECT AVG (players) FROM plays;
You can also create your own aggregates, more documentation on aggregates here: http://cassandra.apache.org/doc/latest/cql/functions.html?highlight=aggregate