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selectjpajpa-2.0jpql
Piotr Sobczyk
Piotr Sobczyk

Reputation: 6583

JPQL statement returning boolean value

Is it possible to write JPQL query like following:

select count(*) > 0 from Scenario scen where scen.name = :name

that would return true/false boolean values depending of whether entity filling criteria exists or not?

I would like to use the query this way: 

boolean exists = entityManager.createQuery(query,Boolean.class).setParameter("name",name).getSingleResult();

The query from my example just isn't syntactically correct (parse error), but is there any correct way of doing checks like that in JPQL, that would return boolean value, or is it only possible in Java code?

Upvotes: 58

Views: 73366

Answers (5)

Simon
Simon

Reputation: 1045

Just use

@Query("select count(scen) > 0 from Scenario scen where scen.name = :name")

Upvotes: 1

Manhattan
Manhattan

Reputation: 171

I had success with:

@Query(nativeQuery = true, value = "select if(count(name) > 0, 'true', 'false') from Scenario scene where scene.name = :name")
Boolean nameExists(@Param("name") String name);

NOTE: I'm using MySQL with MariaDB

Upvotes: 3

Error
Error

Reputation: 91

I was having the same problem, then I updated my hibernate to 4.3.11.Final and now it's working.

Upvotes: 1

Stefan Haberl
Stefan Haberl

Reputation: 10539

What about just:

select count(scen) > 0
from Scenario scen where scen.name = :name

Upvotes: 22

Mikko Maunu
Mikko Maunu

Reputation: 42084

Yes, it is possible with following:

select case when (count(scen) > 0)  then true else false end  
from Scenario scen where scen.name = :name

Upvotes: 95

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