I have a very strange problem.
I have some repository method that accepts Pageable as parameter. Here it is:
#Query(value = "SELECT product_name FROM product WHERE number = 1",
countQuery = "SELECT COUNT (id) FROM product",
nativeQuery = true)
public List<String> getAllProducts(Pageable pageable);
When I use this method without sort inside of pageable everything is okay. Hibernate uses next query in this situation: SELECT product_name FROM product WHERE number = 1 limit ?.
But when I use sort inside of Pageable I get such a strange query: SELECT product_name FROM product WHERE number = 1, product_name asc limit ?.
Do you have any suggestions why spring puts comma instead of ORDER BY?
Related
The Spring Data Jpa Method like this:
#Query("select pb.id,pp.max_borrow_amt,pp.min_borrow_amt
from product_loan_basic pb left join product_loan_price pp on pb.code=pp.product_code
where pb.code IN(?1) and pb.status='publish' order by ?2 ",
nativeQuery = true)
List<Object[]> findByCodesIn(List<String> codes,String orderby);
then order by is " max_borrow_amt desc ", but this is invalid.
the List is disordered.
Dynamic sorting in Spring Data JPA
If you used a JPA query you could use Sort as an argument of your query method to define the sorting order:
#Query("select m from Model m")
List<Model> getSortedList(Sort sort);
and then, for example:
List<Model> models = getSortedList(Sort.by(Sort.Direction.DESC, "name"));
But Spring Data JPA can't use Sort with native queries:
Spring Data JPA does not currently support dynamic sorting for native queries, because it would have to manipulate the actual query declared, which it cannot do reliably for native SQL.
However you can use Pageable and its implementation PageRequest instead:
#Query(value = "select m.name as name from models m", nativeQuery = true)
List<ModelProjection> getSortedList(Pageable p);
and then:
List<ModelProjection> modelNames = getSortedList(PageRequest.of(0, 1000, Sort.Direction.DESC, "name"));
P.S. Instead of array of Objects as returned parameters, it's better to use projections, for example:
public interface ModelProjection {
String getName();
}
Note that in this case the good practice is to use aliases in queries (ie m.name as name). They must match with correspondent getters in the projection.
Working demo and test.
Thanks everyone!
My problem has been solved.
If you want to use Spring data jpa nativeQuery & Sort, you should do like this:
#Query(
value ="select pb.id,pp.max_borrow_amt from product_loan_basic pb left join product_loan_price pp on pb.code=pp.product_code ORDER BY ?#{#pageable} ",
countQuery = "select count(*) from product_loan_basic",
nativeQuery = true
)
Page<Object[]> findAllProductsAndOrderByAndSort(Pageable pageable);
?#{#pageable} is required and countQuery is required.
Pageable pageable = new PageRequest(0,1000,Sort.Direction.DESC,"id");
then the result is sorted.
See Spring Data and Native Query with pagination.
The following query return a list but I am only interested in the last element of the list.
#Query("SELECT r FROM Reservation r WHERE r.reservationSeance.id=:seanceId AND r.seanceDate=:seanceDate")
public Reservation findReservationBySeanceDateAndSeanceId(#Param("seanceId") int seanceId, #Param("seanceDate") java.time.LocalDate seanceDate);
How shall I rewrite the SQL-Query in order to implement my idea?
One possible solution is to use ORDER BY r.id DESC :
#Query("SELECT r FROM Reservation r " +
"WHERE r.reservationSeance.id=:seanceId AND r.seanceDate=:seanceDate " +
"ORDER BY r.id DESC")
public Reservation findReservationBySeanceDateAndSeanceId(
#Param("seanceId") int seanceId,
#Param("seanceDate") java.time.LocalDate seanceDate, Pageable pageable);
and because there are no way to use limit in JPQL, you can use Pageable
Pageable pageable = new PageRequest(0, 1);
Reservation reservation = r.findReservationBySeanceDateAndSeanceId(seanceId, seanceDate, pageable);
Another possible solution without Query :
public Reservation findTop1ByReservationSeanceAndSeanceDateOrderByIdDesc(
ReservationSeanceEntity reservationSenace,
java.time.LocalDate seanceDate
)
In this second solution you have to pass the ReservationSeance Object and not the id of ReservationSeance, the query can be read as :
Find top 1 (first one) by `ReservationSeance` and `SeanceDate` order by `Id` Desc order
You need to provide a couple more parameters to your query, especially an ORDER BY clause.
To get the latest seanceId, you'll want to order your results by that id, but in reverse order. Then, just tell the query to return only the first result:
SELECT r FROM Reservation r
WHERE r.reservationSeance.id=:seanceId
AND r.seanceDate=:seanceDate
ORDER BY seanceId
DESC LIMIT 1;
You can try the following, if you are using mysql as your database:
SELECT r
FROM Reservation r
WHERE r.reservationSeance.id=:seanceId
AND r.seanceDate=:seanceDate
order by r.reservationSeance.id desc limit 0,1
I have a class named Submission and another SubmissionDAO for the repository. The submission class has a number of fields such as id, author, title,...
What I want to do is search through the database and get a list of (count, author) pairs for each author value in the database.
I made a query
#Query(value = "select author, count(*) from submissions GROUP BY author order by count(author) desc", nativeQuery = true)
List<Submission> findByAuthorOccurance();
Obviously, this doesn't work because it can't put the count value in the Submission object.
My question is how would I go about getting this pair of values back to my controller?
I've tried searching but nothing comes up.
In case anyone comes here in the future for whatever reason, I figured my problem out.
When you specify a range of data points to get from the query (ie author and count), it groups the values into object arrays (Object[]) and puts those in a normal List.
So my code ended up being like this:
#Query(value = "select author, count(*) from submissions GROUP BY author order by count(author) desc", nativeQuery = true)
List<Object[]> findByAuthorOccurance();
For the query and
List<Object[]> map =submissionRepository.findByAuthorOccurance();
for(Object[] objs : map){
System.out.println((String)objs[0]+" : "+(BigInteger)objs[1]);
}
To get the data.
Using hql in hibernate we can do pagination on a table data using below, but below will return first 5 data records in the table.
String SQL_QUERY = "FROM Order order";
Query query = session.createQuery(SQL_QUERY);
query.setFirstResult(1);
query.setMaxResults(5);
But how can i do the pagination on a ordered data on a table for example an ordered data set by a order_id ?
Not sure what you're asking, but just add order by clause in your query, and calculate first result based on page. Something like this
String HQL_QUERY = "FROM Order o order by o.id";
Query query = session.createQuery(HQL_QUERY);
// page size
query.setMaxResults(5);
// page 1
query.setFirstResult(1);
// page 2
query.setFirstResult(6);
...
I have a named parameter in JPA typed query. I am setting a list of value in condition.
I am setting a list of integer, but when JPA converts typed query to corresponding sql query it is adding a to_number function and index of the table is not used.
List<Integer> studentIds=ArrayList<Integer>
//Student id is number in database and indexed.
query = "SELECT T.* FROM STUDENT WHERE STUDENT_ID IN (:studentIds)"
TypedQuery<Object[]> typedQuery = entityManager().createQuery( query, Object[].class);
typedQuery.setParameter("studentIds", studentIds);
The issue is when JPA generates the query it is adding to_number function to convert the list
SELECT * from student t4 where student_id in (?,?,?);
filter("T4"."student_id"=TO_NUMBER(:9) OR "T4"."student_id"=TO_NUMBER(:10) OR
"T4"."student_id"=TO_NUMBER(:11) OR "T4"."PRODUCT_SET_ID"=student_id(:12)
Any thoughts how to make sure JPA does not add a to_number function, so index will be used.
I had to use an array when I was passing values into a '.in' predicate. Try this:
List<Integer> studentIds=ArrayList<Integer>
Integer[] ids = new Integer[studentIds.size()];
ids = studentIds.toArray(ids);
//Student id is number in database and indexed.
query = "SELECT T.* FROM STUDENT WHERE STUDENT_ID IN (:studentIds)"
TypedQuery<Object[]> typedQuery = entityManager().createQuery( query, Object[].class);
typedQuery.setParameter("studentIds", ids);