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14.7. The Select Clause

The select clause picks which objects and properties to return in the query result set. Consider the following:
select mate
from Cat as cat
    inner join cat.mate as mate
The query will select mates of other Cats. You can express this query more compactly as:
select cat.mate from Cat cat
Queries can return properties of any value type including properties of component type:
select cat.name from DomesticCat cat
where cat.name like 'fri%'
select cust.name.firstName from Customer as cust
Queries can return multiple objects and/or properties as an array of type Object[]:
select mother, offspr, mate.name
from DomesticCat as mother
    inner join mother.mate as mate
    left outer join mother.kittens as offspr
Or as a List:
select new list(mother, offspr, mate.name)
from DomesticCat as mother
    inner join mother.mate as mate
    left outer join mother.kittens as offspr
Or - assuming that the class Family has an appropriate constructor - as an actual typesafe Java object:
select new Family(mother, mate, offspr)
from DomesticCat as mother
    join mother.mate as mate
    left join mother.kittens as offspr
You can assign aliases to selected expressions using as:
select max(bodyWeight) as max, min(bodyWeight) as min, count(*) as n
from Cat cat
This is most useful when used together with select new map:
select new map( max(bodyWeight) as max, min(bodyWeight) as min, count(*) as n )
from Cat cat
This query returns a Map from aliases to selected values.