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I need to bring from DB only one single result. How can I do that with JPA?
Select top 1 * from table I tried
"select t from table t"
query.setMaxResults(1); query.getSingleResult(); but didn't work. Any other ideas?
606
JPA Setup In our repository method, we use the EntityManager to create a Query on which we call the setMaxResults() method. This call to Query#setMaxResults will eventually result in the limit statement appended to the generated SQL: select passenger0_.id as id1_15_, passenger0_.
JPQL does not provide a mechanism to limit queries. This is most often achieved by using the setMaxResults() method on the Query . If you must avoid specifying this in Java code, you could make a view in the database that contains your query and performs the limit.
If a given JPA GROUP BY query returns only two columns where one is unique, it's very suitable to return the result as a Java Map. For this, you can use either the Java Stream functionality or the Hibernate-specific ResultTransformer .
Its findById method retrieves an entity by its id. The return value is Optional<T> . Optional<T> is a container object which may or may not contain a non-null value. If a value is present, isPresent returns true and get returns the value.
Try like this
String sql = "SELECT t FROM table t"; Query query = em.createQuery(sql); query.setFirstResult(firstPosition); query.setMaxResults(numberOfRecords); List result = query.getResultList(); It should work
UPDATE*
You can also try like this
query.setMaxResults(1).getResultList(); To use getSingleResult on a TypedQuery you can use
query.setFirstResult(0); query.setMaxResults(1); result = query.getSingleResult(); If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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