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7.5. Aggregate functions

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
  • avg(...), avg(distinct ...), sum(...), sum(distinct ...), min(...), max(...)
  • count(*)
  • count(...), count(distinct ...), count(all...)
You may use arithmetic operators, concatenation, and recognized SQL functions in the select clause (depending on configured dialect, HQL specific feature):
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