JPA Criteria select all instances with max values in their groups - jpa

Is there a way to write with JPA 2 CriteriaBuilder the equivalent of the following query?
select * from season s1
where end = (
select max(end)
from season s2
where s1.contest_id=s2.contest_id
);
In JPQL this query is:
Select s1 from Season s1
where s1.end = (
select max(s2.end)
from Season s2
where s1.contest=s2.contest
)

This should work, with contest being either a basic Integer property, or a ManyToOne property pointing to another non-basic Entity.
EntityManger em; //to be injected or constructed
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Season> cq = cb.createQuery(Season.class);
Subquery<Date> sq = cq.subquery(Date.class);
Root<Season> s1 = cq.from(Season.class);
Root<Season> s2 = sq.from(Season.class);
sq.select(cb.greatest(s2.get(Season_.end)));
sq.where(cb.equal(s2.get(Season_.contest), s1.get(Season_.contest)));
cq.where(cb.equal(s1.get(Season_.end), sq));
List<Season> result = em.createQuery(cq).getResultList();

Related

JPA Criteria orderBy: unexpected AST node

I have the following criteria query, which retrieves some fields from Anfrage and Sparte entities and also the translated string for the sparte.i18nKey.
This works as expected if I dont use orderBy.
Now I have the requirement to sort by the translated string for sparte.i18nKey and using the orderBy as shown below, results in QuerySyntaxException: unexpected AST node
So the problem must be the subselect in the orderBy clause!
select distinct new
my.domain.model.dto.AnfrageDTO(
anfrage0.id,
anfrage0.name,
anfrage0.sparte.id,
anfrage0.sparte.i18nKey,
-- retrieve translated string for sparte.i18nKey
(select rb0.value from at.luxbau.mis2.domain.model.ResourceBundleEntity as rb0
where (anfrage0.sparte.i18nKey = rb0.key) and (rb0.language = 'de'))
)
from my.domain.model.impl.Anfrage as anfrage0
left join anfrage0.sparte as sparte
order by (
-- sort by translated string for sparte.i18nKey
select rb1.value
from my.domain.model.ResourceBundleEntity as rb1
where (anfrage0.sparte.i18nKey = rb1.key) and (rb1.language = 'de')
) asc
My Java code looks like this:
private List<AnfrageDTO> getAnfragen() {
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<AnfrageDTO> query = cb.createQuery(AnfrageDTO.class);
Root<Anfrage> anfrage = query.from(Anfrage.class);
anfrage.join(Anfrage_.sparte, JoinType.LEFT);
query.select(cb.construct(AnfrageDTO.class,
anfrage.get(Anfrage_.id),
anfrage.get(Anfrage_.name),
anfrage.get(Anfrage_.sparte).get(Sparte_.id),
anfrage.get(Anfrage_.sparte).get(Sparte_.i18nKey),
// create subquery for translated sparte.i18nKey
createResourceBundleSubQuery(cb, query, anfrage.get(Anfrage_.sparte).get(Sparte_.i18nKey)).getSelection()));
TypedQuery<AnfrageDTO> tq = entityManager
.createQuery(query)
// use subquery to sort by translated sparte.i18nKey
.orderBy(cb.asc(createResourceBundleSubQuery(cb, query, anfrage.get(Anfrage_.sparte).get(Sparte_.i18nKey))));
tq.setMaxResults(10);
List<AnfrageDTO> anfragen = tq.getResultList();
return anfragen;
}
public Subquery<String> createResourceBundleSubQuery(CriteriaBuilder cb, CriteriaQuery<?> query, <String> expr) {
Subquery<String> subquery = query.subquery(String.class);
Root<ResourceBundleEntity> rb = subquery.from(ResourceBundleEntity.class);
subquery
.select(rb.get(ResourceBundleEntity_.value))
.where(cb.and(
cb.equal(expr, rb.get(ResourceBundleEntity_.key)),
cb.equal(rb.get(ResourceBundleEntity_.language), "de")));
return subquery;
}
Using a native SQL query with subselect in orderBy works also as expected.
select distinct
anfrage0_.id,
anfrage0_.name,
anfrage0_.sparte_id,
sparte4_.i18n_key,
(select rb3.i18n_value from resource_bundle rb3 where rb3.language_code = 'de' and rb3.i18n_key = sparte4_.i18n_key) as sparte_i18n_value
from
mis2.anfrage anfrage0_
left outer join mis2.sparte sparte4_ on anfrage0_.sparte_id = sparte4_.id
order by (
select rb.i18n_value
from mis2.resource_bundle rb
where sparte4_.i18n_key = rb.i18n_key and rb.language_code = 'de'
) asc
Also using an alias in the native SQL query works also as expected.
select distinct
anfrage0_.id,
anfrage0_.name,
anfrage0_.sparte_id,
sparte4_.i18n_key,
(select rb3.i18n_value from resource_bundle rb3 where rb3.language_code = 'de' and rb3.i18n_key = sparte4_.i18n_key) as sparte_i18n_value
from
mis2.anfrage anfrage0_
left outer join mis2.sparte sparte4_ on anfrage0_.sparte_id = sparte4_.id
order by sparte_i18n_value
asc
It would be great if JPA Criteria API would support using an alias in orderBy clause!
Any hints welcome - Thank you!
My environment is WildFly 11 and PostgreSQL 9.6.
JPA doesn't support passing parameter in order by clause, your problem has been asked before: Hibernate Named Query Order By parameter

JPA criteria, where count > 0

I have 2 tables:
Client
Invoice
Client has an OneToMany association, to list the invoices.
I want to use CriteriaBuilder to create this select:
select
...
from
Client c
where
(select count(1) from Invoice i where i.id = c.invoiceId) > 0
How can I do this?
with JPQL you can use :
Query query = em.createQuery
("SELECT c FROM Client c WHERE (SELECT COUNT(i) FROM Invoice i WHERE i.client= c) > 0");
List<Client> clientc=query.getResultList());
but with Criteria API as you are using subquery in where clause you need something like below (maybe it's not exactly what you want I'm not sure because didn't test I just write it):
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Client> q = cb.createQuery(Client.class);
Root<Client> client = q.from(Client.class);
q.select(client);
Subquery<Invoice> sq= q.subquery(Invoice.class);
Root<Invoice> invoice= sq.from(Invoice.class);
sq.select(invoice);
Predicate sqp = cb.equal(client.get("id"), invoice.get("invoiceId"));
sq.where(sqp);
q.where(cb.exists(sq));

JPA Criteria Equivalent Query Subquery greatest or max

This SQL query does exactly what is needed when executed. I am looking for the JPA Criteria equivalent? Basically gets the Device entity and the LATEST(greatest) GPS coord from a One-To-Many relationship
SELECT DISTINCT t0.DEVICE_I, t0.ACTIVE_S, t0.APP_CONFIG_I, t0.PREV_APP_CONFIG_I,
t0.APP_CONFIG_CONFIRMED_S, t0.APP_CONFIG_RECEIPT_D, t0.APP_CONFIG_SENT_S, t0.CHANNEL_X,
t0.CREATION_TS, t0.CREATION_USER_I, t0.DEST_QUEUE_C, t0.DIVISION_C, t0.LAN_IP_X,
t0.LAST_UPDATE_TS, t0.LAST_UPDATE_USER_I, t0.MOBILE_IP_X, t0.ORIGIN_MP_I,
t0.PREV_CHANNEL_X, t0.TELEPHONE_NUMBER_X, t0.VERSION_X, t1.DEVICE_I, t1.COORDINATE_I,
t1.CREATION_TS, t1.CREATION_USER_I, t1.GENERATED_TS, t1.GPGGA_X, t1.GPGSA_X,
t1.GPGSV_X, t1.GPRMC_X, t1.GPVTG_X, t1.LAST_UPDATE_TS, t1.LAST_UPDATE_USER_I,
t1.WORK_ORDER_NUMBER_I
FROM DEVICE t0, GPS_COORD t1
WHERE t0.DEVICE_I = t1.DEVICE_I AND
t1.GENERATED_TS IN ( select max(GENERATED_TS)
from GPS_COORD
group by DEVICE_I )
ORDER BY t1.DEVICE_I ASC, t1.GENERATED_TS DESC
The java code below is almost there and generates the following query which is missing joined fields needed from GpsCoord. These fields are included if a fetch is done, but the Join is necessary later in the where clause of the Subquery:
CriteriaBuilder criteriaBuilder = em.getCriteriaBuilder();
CriteriaQuery<Device> cq = criteriaBuilder.createQuery(Device.class);
Root<Device> device = cq.from(Device.class);
cq.distinct(true);
Join<Device, GpsCoord> j = device.join(Device_.gpsCoords, JoinType.LEFT);
//Fetch<Device,GpsCoord> f = device.fetch(Device_.gpsCoords);
CriteriaQuery<Device> select = cq.select(device);
Subquery<Timestamp> sq = cq.subquery(Timestamp.class);
Root<GpsCoord> gpsCoord = sq.from(GpsCoord.class);
sq.select(criteriaBuilder.greatest(gpsCoord.get(GpsCoord_.generatedTs)));
sq.groupBy(gpsCoord.get(GpsCoord_.device).get(Device_.deviceI));
select.where(j.get(GpsCoord_.generatedTs).in(sq));
TypedQuery<Device> query = this.getEntityManager().createQuery(cq);
Query that is generated is missing the GpsCoord fileds from the Join oepration
SELECT DISTINCT t0.DEVICE_I, t0.ACTIVE_S, t0.APP_CONFIG_I, t0.PREV_APP_CONFIG_I,
t0.APP_CONFIG_CONFIRMED_S, t0.APP_CONFIG_RECEIPT_D, t0.APP_CONFIG_SENT_S,
t0.CHANNEL_X, t0.CREATION_TS, t0.CREATION_USER_I, t0.DEST_QUEUE_C, t0.DIVISION_C,
t0.LAN_IP_X, t0.LAST_UPDATE_TS, t0.LAST_UPDATE_USER_I, t0.MOBILE_IP_X, t0.ORIGIN_MP_I,
t0.PREV_CHANNEL_X, t0.TELEPHONE_NUMBER_X, t0.VERSION_X
FROM SPW_OWN.DEVICE t0, SPW_OWN.GPS_COORD t1
WHERE (t1.GENERATED_TS IN (SELECT MAX(t2.GENERATED_TS) FROM SPW_OWN.GPS_COORD t2,
SPW_OWN.DEVICE t3 WHERE t2.DEVICE_I = t3.DEVICE_I GROUP BY t3.DEVICE_I))
AND t0.DEVICE_I = t1.DEVICE_I(+)
Using a multiselect from the CriteriaQuery like this generates the proper SQL when executed, but the following exception
Caused by: java.lang.Exception: java.lang.RuntimeException: Can not find constructor for "class Device" with argument types "[class java.lang.String ... java.sql.Timestamp]" to fill data.
gets thrown after the call:
CriteriaQuery<Device> select = cq.multiselect(
//"deviceI",
device.get(Device_.deviceI),
//"activeS",
device.get(Device_.activeS),
//"appConfigConfirmedS",
device.get(Device_.appConfigConfirmedS),
//"appConfigReceiptD",
device.get(Device_.appConfigReceiptD),
//"appConfigSentS",
device.get(Device_.appConfigSentS),
//"channelX",
device.get(Device_.channelX),
//"destQueueC",
device.get(Device_.destQueueC),
//"lanIpX",
device.get(Device_.lanIpX),
//"mobileIpX",
device.get(Device_.mobileIpX),
//"prevChannelX",
device.get(Device_.prevChannelX),
//"telephoneNumberX",
device.get(Device_.telephoneNumberX),
//"versionX"
device.get(Device_.versionX),
//"device",
j.get(GpsCoord_.device),
//"gpggaX",
j.get(GpsCoord_.gpggaX),
//"gprmcX",
j.get(GpsCoord_.gprmcX),
//"gpgsaX",
j.get(GpsCoord_.gpgsaX),
//"gpgsvX",
j.get(GpsCoord_.gpgsvX),
//"gpvtgX"
j.get(GpsCoord_.gpvtgX),
j.get(GpsCoord_.generatedTs)
);
A few issues,
you call, sq.from(GpsCoord.class); twice
using device.fetch(Device_.gpsCoords); will also fetch the object, and will join it twice
you IN is incorrect it should be,
select.where(criteriaBuilder.get(path).in(sq));

Linq: the linked objects are null, why?

I have several linked tables (entities). I'm trying to get the entities using the following linq:
ObjectQuery<Location> locations = context.Location;
ObjectQuery<ProductPrice> productPrice = context.ProductPrice;
ObjectQuery<Product> products = context.Product;
IQueryable<ProductPrice> res1 = from pp in productPrice
join loc in locations
on pp.Location equals loc
join prod in products
on pp.Product equals prod
where prod.Title.ToLower().IndexOf(Word.ToLower()) > -1
select pp;
This query returns 2 records, ProductPrice objects that have linked object Location and Product but they are null and I cannot understand why. If I try to fill them in the linq as below:
res =
from pp in productPrice
join loc in locations
on pp.Location equals loc
join prod in products
on pp.Product equals prod
where prod.Title.ToLower().IndexOf(Word.ToLower()) > -1
select new ProductPrice
{
ProductPriceId = pp.ProductPriceId,
Product = prod
};
I have the exception "The entity or complex type 'PBExplorerData.ProductPrice' cannot be constructed in a LINQ to Entities query"
Could someone please explain me what happens and what I need to do?
Thanks
The answer to your first question the Product and Location are null because you need to add an Include("") to your query.
IQueryable<ProductPrice> res1 = from pp in
productPrice.Include("Location").Include("Product")
join loc in locations
on pp.Location equals loc
join prod in products
on pp.Product equals prod
where prod.Title.ToLower().IndexOf(Word.ToLower()) > -1
select pp;
The second issue is EF is trying to push down your query and ProductPrice (is not an entity) so it can not. If you want to do this convert it to an anonymous type so just do
select new
{
ProductPriceId = pp.ProductPriceId,
Product = prod
};
And then do
res.ToList().ConvertAll(x=new ProductPrice () {
ProductPriceId = x.ProductPriceId ,
Product = x.Product
});
Or you could do it other ways, by selecting the entity you want, and just populating manual.

Can some one help me to conver it into LINQ i m using Entity Framework

select ForumCategories.ID , ForumCategories.Title , ForumCategories.DateCreated,
CO = ( select COUNT(*) from ForumSubCategories where ForumSubCategories.CategoryID_FK = ForumCategories.ID)
from ForumCategories
var q = from fc in Context.ForumCategories
select new
{
Id = fc.ID,
Title = fc.Title,
DateCreated = fc.DateCreated
CO = fc.ForumSubCategories.Count()
};
return q;
The "join" (subquery) is implicit; it's defined in the relationship between ForumCategories and ForumSubCategories in your model. Using this syntax, the call to Count() will be done on the DB server.