Spring Data Jpa specification implementation of given problem
Spring Data Jpa specification implementation of given problem
I am having a table like
ColA ColB
Name1 1
Name1 2
Name2 1
Name2 3
Name2 5
I want to fetch my result set as
ColA ColB
Name1 1
Name2 1
How can we implement it in spring data JPA specification ?
I think you have to describe your case more detailed. I mean, e.g tell us more about which values you want to pass to query to achive this result and other helpful information which we allow us to answer your question more precisely.
– Kamil W.
Sep 10 '18 at 9:42
I need not pass any values into it. I just want to print min value of ColB corresponding to a Name. Ex: Name1 has a min value of 1, Name2 has a min value of 1
– deepak asai
Sep 10 '18 at 9:49
yes min function in available in Specification
– Narayan Yerrabachu
Sep 10 '18 at 11:40
It's impossible in Spring Data JPA using Specification to achieve what you want because Specification affects only the WHERE clause of the SQL statement whereas you need SQL GROUB BY and MIN functionality.
– Robert Niestroj
Sep 10 '18 at 13:11
1 Answer
1
Add below code in your repository interface. I think it should work.
@Async
@Query(value = "select * " +
" from TableA ta " +
"where ta.colb = :colb",nativeQuery=true)
List<T> findByColA(@Param("colb") String colb);
or
with specification
Create Specification Object:
Criteria functions(SUM, MAX or MIN) for Specification:
javax.persistence.criteria.CriteriaQuery<T> Check this interface to find more information.
javax.persistence.criteria.CriteriaQuery<T>
final class UserSpecifications
private UserSpecifications()
static Specification<User> findData(String colb, String columnName)
return new Specification<User>()
public Predicate toPredicate(Root<User> root,
CriteriaQuery<?> query,
CriteriaBuilder cb)
root = query.from(User.class);
Predicate colbp = cb.equal(root.get(columnName), colb);
Expression<String> groupByExp = root.get(columnname).as(String.class);
query.where(colbp);
query.select(cb.min(root.get(column.getName())));
query.groupBy(groupByExp);
Specification<User> spec = UserSpecifications.findData("1", "columnName");
List<User> allUsers = repository.findAll(spec);
Tutorial :Spring data Tutorial
specification example: Spring Data specification
Spring Specification example:Spring Specification How-to
Stackoverflow ref: Spring Specification
I want to use with Specification. So that i can pass findAll(specification)
– deepak asai
Sep 10 '18 at 10:03
yes u can also do it with specification List<T> findAll(Specification<T> spec);
– Narayan Yerrabachu
Sep 10 '18 at 10:06
My doubt is how to construct that Specification Object.
– deepak asai
Sep 10 '18 at 10:16
baeldung.com/…
– Narayan Yerrabachu
Sep 10 '18 at 10:35
My doubt is to how to implement Max and min functions and spring data JPA. Because i dont think so it is easy to construct Specification object for my problem. Can some clearly construct a specification object for my proble
– deepak asai
Sep 10 '18 at 11:07
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Why does ColB mean in your expected output?
– sp00m
Sep 10 '18 at 9:40