HQL queries may even return the results of aggregate functions on properties:

select avg(cat.weight), sum(cat.weight), max(cat.weight), count(cat)
from Cat cat

The supported aggregate functions are

You may use arithmetic operators, concatenation, and recognized SQL functions in the select clause:

select cat.weight + sum(kitten.weight)
from Cat cat
    join cat.kittens kitten
group by cat.id, cat.weight

select firstName||' '||initial||' '||upper(lastName) from Person

The distinct and all keywords may be used and have the same semantics as in SQL.

select distinct cat.name from Cat cat

select count(distinct cat.name), count(cat) from Cat cat