Inner join when it should be left join in JPA - java

I'm using JpaRepository and I'm creating a #Query in my repository:
this is my query:
#Query( "SELECT SUM(p.prima) as prima, p.producto as producto, p.tipoProducto as tipoProducto, p.compania as compania, p.cliente as cliente, p.vendedor as vendedor " +
"FROM Poliza p " +
"JOIN Producto pr ON p.producto=pr " +
"JOIN TipoProducto tp ON p.tipoProducto=tp " +
"JOIN Compania c ON p.compania=c " +
"JOIN Cliente cl ON p.cliente=cl " +
"LEFT JOIN Vendedor v ON p.vendedor=v " +
"WHERE p.comienzo >=?1 " +
"AND p.comienzo <= ?2 " +
"GROUP BY p.producto")
and I realize that I only get the rows where "Vendedor" is present.
I used the spring.jpa.show-sql=true property to check what was going on and I realize that the query is creating an inner join for each property in the SELECT STATEMENT
inner join producto producto1_ on (poliza0_.producto=producto1_.id)
inner join tipo_producto tipoproduc2_ on (poliza0_.tipo_producto=tipoproduc2_.id)
inner join compania compania3_ on (poliza0_.compania=compania3_.id)
inner join cliente cliente4_ on (poliza0_.cliente=cliente4_.id)
inner join vendedor vendedor5_ on (poliza0_.vendedor=vendedor5_.id)
join producto producto6_ on poliza0_.producto=producto6_.id
join tipo_producto tipoproduc7_ on poliza0_.tipo_producto=tipoproduc7_.id
join compania compania8_ on poliza0_.compania=compania8_.id
join cliente cliente9_ on poliza0_.cliente=cliente9_.id
left join vendedor vendedor10_ on poliza0_.vendedor=vendedor10_.id
As you can see in the first part I have an inner join from Vendedor which makes the query wrong.
How should I create my query to get the expected result?

if understand clearly
#Query( "SELECT SUM(p.prima) as prima, p.producto as producto, p.tipoProducto as tipoProducto, p.compania as compania, p.cliente as cliente, p.vendedor as vendedor " +
"FROM Poliza p " +
"JOIN Producto pr ON p.producto=pr " +
"JOIN TipoProducto tp ON p.tipoProducto=tp " +
"JOIN Compania c ON p.compania=c " +
"JOIN Cliente cl ON p.cliente=cl " +
"LEFT JOIN Vendedor v ON p.vendedor=v " +
"WHERE p.comienzo >=?1 " +
"AND p.comienzo <= ?2 " +
"GROUP BY p.producto")
i think you can using v instead p.vendedor as vendedor in select field.

If I read correctly, you are defining your own query. So, you can edit the JOIN in your query and write LEFT JOIN instead.
Am I right on your intentions?

Related

incorrect #query in spring boot

I am trying to use this query in springboot so I can display the results in a webpage. I know that this query works because I tested it in postgresql and it gave me the right results.
But JPA is telling me that the '(' after the first FROM is an unexpected token and the query was therefore viewed as invalid.
This is my query:
#Query(
"SELECT com.example.imse22.model.TrvlA_Cust_Dto(books_query.name, count(travelA_query.customer_id)) " +
"FROM (SELECT DISTINCT customer_servant.employee_id, books.customer_id FROM customer_servant " +
"INNER JOIN books ON customer_servant.employee_id = books.customer_servant_id) AS travelA_query " +
"INNER JOIN " +
"(SELECT travel_agency.id, travel_agency.name, employee.employee_id FROM travel_agency " +
"INNER JOIN employee ON travel_agency.id = employee.travel_agency_id) AS books_query " +
"ON travelA_query.employee_id = books_query.employee_id " +
"GROUOP BY travelA_query.name")
can somebody help me out how I could rewrite the query so that JPA approves it?
Your query is native so you should declare it in that way:
#Query(
value = "SELECT com.example.imse22.model.TrvlA_Cust_Dto(books_query.name, count(travelA_query.customer_id)) " +
"FROM (SELECT DISTINCT customer_servant.employee_id, books.customer_id FROM customer_servant " +
"INNER JOIN books ON customer_servant.employee_id = books.customer_servant_id) AS travelA_query " +
"INNER JOIN " +
"(SELECT travel_agency.id, travel_agency.name, employee.employee_id FROM travel_agency " +
"INNER JOIN employee ON travel_agency.id = employee.travel_agency_id) AS books_query " +
"ON travelA_query.employee_id = books_query.employee_id " +
"GROUOP BY travelA_query.name", nativeQuery = true)
link point 2.2: https://www.baeldung.com/spring-data-jpa-query
Ok so this is how I solved it:
I changed my query into a native one just like #notAPPP pointed out and then I only had to add an alias for the LEFT JOIN (also I changed INNER JOIN to LEFT JOIN).
here the code example:
#Query(value = "SELECT combined.name as name, count(combined.customer_id) as id " +
"FROM (" +
"(SELECT travel_agency.name, travel_agency.id, employee.employee_id " +
"FROM travel_agency INNER JOIN employee ON travel_agency.id = employee.travel_agency_id) as trvlEmp " +
"LEFT JOIN " +
"(SELECT books.customer_id, books.customer_servant_id, customer_servant.employee_id " +
"FROM books INNER JOIN customer_servant ON books.customer_servant_id = customer_servant.employee_id) as custBooks " +
"ON trvlEmp.employee_id = custBooks.employee_id) as combined " + // this "AS combined" got added
"GROUP BY combined.name", nativeQuery = true)
This makes sense, because after a FROM clause one should wirte the name of a table or a result table (e.g. from two joined queries like in my case). As I didnt specify an alias for the LEFT JOIN of my two subqueries, JPA obviously didnt know how to handle the result of those subqueries. Therefore always name your subqueries if they are not used in a WHERE clause, but rather with a FROM clause, like in my case. E.g. the name I gave my LEFT JOIN is "combined" as seen in the code example above.
Also I changed my INNER JOIN to a LEFT JOIN to get the value 0 of the elements that have 0 counts of what I wanted to count in the table.
If you want to know how to handle the result which such a query returns follow this link.thorben-janssen.com/spring-data-jpa-dto-native-queries

Is it possible to use window functions in JPA?

I need to use window functions within a Spring Data Repository, is
this possible?
I am now using java spring maven and I have no knowledge about the entity table partition in JPA.
My SQL Query
select
b.q_stop_id as q_stop_id,
b.q_work_day as q_work_day,
b.q_work_end as q_work_end,
b.q_mc_num as q_mc_num,
b.q_mc_name as q_mc_name,
b.Hnbn as q_hnbn,
b.q_koku as q_koku,
b.q_stop_st_time as q_stop_st_time,
b.q_stop_en_time as q_stop_en_time,
b.q_stop_time_s as q_stop_time_s,
b.q_stop_maj_code as q_stop_maj_code,
b.q_stop_major as q_stop_major,
b.q_stop_num as q_stop_num,
b.q_stop_minor as q_stop_minor,
b.q_pause_flag as q_pause_flag
from
(
select ROW_NUMBER() OVER (PARTITION BY a.rnk
ORDER BY a.q_stop_st_time,a.q_stop_en_time) AS RowNo,COUNT(*) OVER () as cnt,*
from (
select DENSE_RANK() OVER(PARTITION BY proL.q_set_hnbn ORDER BY stL.q_stop_st_time,stL.q_stop_en_time DESC) as rnk,case when proL.q_set_hnbn is not null and proL.q_set_hnbn !='' then proL.q_set_hnbn else proL.q_hnbn end as Hnbn ,proL.q_set_hnbn as setHnbn, stL.q_stop_id as q_stop_id,wk.q_work_day as q_work_day,wk.q_work_end as q_work_end,mc.q_mc_num as q_mc_num,mc.q_mc_name as q_mc_name,proL.q_hnbn as q_hnbn,proL.q_koku as q_koku,stL.q_stop_st_time as q_stop_st_time,stL.q_stop_en_time as q_stop_en_time,stL.q_stop_time_s as q_stop_time_s,mst.q_stop_maj_code as q_stop_maj_code,mst.q_stop_major as q_stop_major,mst.q_stop_num as q_stop_num,mst.q_stop_minor as q_stop_minor,
mst.q_pause_flag as q_pause_flag
from T_STOP_LOG stL inner join M_stop_item mst on stL.q_stop_num=mst.q_stop_num
inner join T_work_log wk on stL.q_work_id=wk.q_work_id
inner join T_prod_log proL on wk.q_work_id =proL.q_work_id
inner join M_mc mc on wk.q_mc_num=mc.q_mc_num
left join T_malfunction_repair_log r on r.q_stop_id=stL.q_stop_id
where wk.q_work_day >='2021-04-19 00:00:00.000' and
wk.q_work_end<='2021-04-20 23:59:59.000' and mc.q_mc_num='1200' )a
)b where b.RowNo=1 or b.RowNo=2
> I found the solution by using JPA nativeQuery = true
#Query(value = "select " + "b.q_stop_id as q_stop_id," + "b.q_work_day as q_work_day,"
+ "b.q_work_end as q_work_end," + "b.q_mc_num as q_mc_num," + "b.q_mc_name as q_mc_name,"
+ "b.Hnbn as q_hnbn," + "b.q_koku as q_koku," + "b.q_stop_st_time as q_stop_st_time,"
+ "b.q_stop_en_time as q_stop_en_time," + "b.q_stop_time_s as q_stop_time_s,"
+ "b.q_stop_maj_code as q_stop_maj_code," + "b.q_stop_major as q_stop_major,"
+ "b.q_stop_num as q_stop_num," + "b.q_stop_minor as q_stop_minor," + "b.q_pause_flag as q_pause_flag "
+ "from" + "(" + "select ROW_NUMBER() OVER (PARTITION BY a.rnk "
+ "ORDER BY a.q_stop_st_time,a.q_stop_en_time) AS RowNo,COUNT(*) OVER () as cnt,* "
+ "from (select DENSE_RANK() OVER(PARTITION BY proL.q_set_hnbn ORDER BY stL.q_stop_st_time,stL.q_stop_en_time DESC) as rnk,case when proL.q_set_hnbn is not null and proL.q_set_hnbn !='' then proL.q_set_hnbn else proL.q_hnbn end as Hnbn ,proL.q_set_hnbn as setHnbn,stL.q_stop_id as q_stop_id,wk.q_work_day as q_work_day,wk.q_work_end as q_work_end,mc.q_mc_num as q_mc_num,mc.q_mc_name as q_mc_name,proL.q_hnbn as q_hnbn,proL.q_koku as q_koku,stL.q_stop_st_time as q_stop_st_time,stL.q_stop_en_time as q_stop_en_time,stL.q_stop_time_s as q_stop_time_s,mst.q_stop_maj_code as q_stop_maj_code,mst.q_stop_major as q_stop_major,mst.q_stop_num as q_stop_num,mst.q_stop_minor as q_stop_minor,"
+ "mst.q_pause_flag as q_pause_flag "
+ "from T_STOP_LOG stL inner join M_stop_item mst on stL.q_stop_num=mst.q_stop_num "
+ "inner join T_work_log wk on stL.q_work_id=wk.q_work_id "
+ "inner join T_prod_log proL on wk.q_work_id =proL.q_work_id "
+ "inner join M_mc mc on wk.q_mc_num=mc.q_mc_num "
+ "left join T_malfunction_repair_log r on r.q_stop_id=stL.q_stop_id "
+ "where wk.q_work_day >=:workDay and wk.q_work_end<=:workEnd and mc.q_mc_num=:kiban)a "
+ ")b where b.RowNo=1 or b.RowNo=2", nativeQuery = true)

Eagerly load nested association using HQL

I have the following model:
public class BaseModel {
List<DataA> lazyCollectionA;
List<DataB> lazyCollectionB;
}
public class DataA {
OtherEntity otherEntity;
}
public class OtherEntity {
List<DataC> lazyCollectionC;
}
When I visit a particular page I need to use all this data. This is creating a performance select n+1 problem.
I already partly solved the issue by eagerly fetching the collections using:
List<BaseModel> result = entityManager.createQuery(
"select m from BaseModel m " +
"left join fetch m.lazyCollectionA " +
"where m.id in (:ids) ", BaseModel.class)
.setParameter("ids", ids)
.getResultList();
result = entityManager.createQuery(
"select m from BaseModel m " +
"left join fetch m.lazyCollectionB " +
"where m.id in (:ids) ", BaseModel.class)
.setParameter("ids", ids)
.getResultList();
Note that I had to perform 2 queries instead of only 1 because otherwise I would get a MultipleBagFetchException.
However, I'm having problems eagerly loading lazyCollectionA.otherEntity.lazyCollectionC. I tried several variations of the query to try to eagerly fetch the results, but when otherEntity.lazyCollectionC is accessed, the select n+1 problem keeps surfacing.
I think this should work, but unfortunately it is not:
entityManager.createQuery(
"select a from BaseModel m " +
"left join m.lazyCollectionA a " +
"left join fetch a.otherEntity o " +
"left join fetch o.lazyCollectionC " +
"where m.id in (:ids) ", BaseModel.class)
.setParameter("ids", ids)
.getResultList();
Do you have any ideas why this is not working?
Also, I don't fully understand how my first 2 queries to load lazyCollectionA and lazyCollectionB are working. I mean, since they are loaded at different times, I would expect that only the last query would have the loaded instances. Is it because hibernate is caching the results and therefore it does not need to query the database again?
Thanks for any help you can provide!
I assume that all connections between your models are #OneToMany. In this case you could try simething like this:
#Autowired
private EntityManager em;
#Transactional
public List<BaseModel> getAllByThreeQueries() {
List<Long> ids = Arrays.asList(1L);
List<BaseModel> first = em.createQuery(
"select distinct m from BaseModel m " +
"left join fetch m.lazyCollectionB " +
"where m.id in (:ids) ", BaseModel.class)
.setParameter("ids", ids)
.getResultList();
List<BaseModel> second = em.createQuery(
"select distinct m from BaseModel m " +
"left join fetch m.lazyCollectionA a " +
"left join fetch a.otherEntity o " +
"where m in (:models) ", BaseModel.class)
.setParameter("models", first)
.getResultList();
em.createQuery("select distinct a from BaseModel m " +
"left join m.lazyCollectionA a " +
"left join fetch a.otherEntity o " +
"left join fetch o.lazyCollectionC " +
"where m in (:models) ", DataA.class)
.setParameter("models", second)
.getResultList();
return second;
}
Full code
Do you have any ideas why this is not working?
entityManager.createQuery(
"select a from BaseModel m " +
"left join m.lazyCollectionA a " +
"left join fetch a.otherEntity o " +
"left join fetch o.lazyCollectionC " +
"where m.id in (:ids) ", BaseModel.class)
.setParameter("ids", ids)
.getResultList();
Because you get a MultipleBagFetchException in this case. You need to do one more request.

How to implement JPQL query?

I have working query in PostgreSQL:
select s.id, s.seat_number as available_seat, s.row_number as available_row, rm.room_name as screening_room
from seats s
join rooms rm on rm.id=s.room_id
left join (
select r.seat_id from reserved_seats r
join reservations res on res.id=r.reservation_id AND res.screening_id = 3 ) res on res.seat_id=s.id
where res.seat_id is null AND s.room_id=3
ORDER BY s.id;
But I make mistakes translating it into the JPA query language.
Can I use nested SELECTs in JPQL?
The answer is to use native query:
#Query(value =
"SELECT s.id seatId, s.seat_number availableSeat, " +
"s.row_number availableRow, rm.name screeningRoom \n" +
"FROM seats s\n" +
"JOIN rooms rm on rm.id=s.room_id\n" +
" LEFT JOIN (\n" +
" SELECT r.seat_id FROM reserved_seats r\n" +
" JOIN reservations res ON res.id=r.reservation_id " +
" AND res.screening_id = :screeningId) res ON res.seat_id=s.id\n" +
"WHERE res.seat_id IS NULL AND s.room_id=:roomId AND s.row_number=:rowNumber\n" +
"ORDER BY s.id;", nativeQuery = true)
The answer is to use native query:
#Query(value =
"SELECT s.id seatId, s.seat_number availableSeat, " +
"s.row_number availableRow, rm.name screeningRoom \n" +
"FROM seats s\n" +
"JOIN rooms rm on rm.id=s.room_id\n" +
" LEFT JOIN (\n" +
" SELECT r.seat_id FROM reserved_seats r\n" +
" JOIN reservations res ON res.id=r.reservation_id " +
" AND res.screening_id = :screeningId) res ON res.seat_id=s.id\n" +
"WHERE res.seat_id IS NULL AND s.room_id=:roomId AND s.row_number=:rowNumber\n" +
"ORDER BY s.id;", nativeQuery = true)

Can we limit records by using named queries?

There are about 20000 records in my DB but I only want to fetch 500 records at a time. I am using named queries for fetching data. So, how can I put a limit to named queries?
I tried like this,
#NamedQuery(name = "qryChildEventByOrganization", query = "select childEvent from ChildEvent childEvent limit 500"
+ "left outer join fetch childEvent.child as ceChild "
+ "left outer join fetch ceChild.address as address "
+ "left outer join fetch ceChild.user as cuser "
+ "left outer join fetch childEvent.user as ceuser "
+ "left outer join fetch cuser.address as caddress "
+ "left outer join fetch ceuser.address as ceaddress "
+ "left outer join fetch ceChild.immunization as cimmunization "
+ "left outer join fetch ceChild.insurance as cinsurance "
+ "left outer join fetch ceChild.healthHistory as chealthHistory "
+ "left outer join fetch ceChild.emergencyContact as cemergencyContact "
+ "left outer join fetch ceChild.doctor as cdoctor "
+ "left outer join fetch ceChild.dietActivityRestriction as cdietActivityRestriction "
+ "left outer join fetch ceChild.allergy as cAllergy "
+ "left outer join fetch ceChild.medication as cMedication "
+ "left outer join fetch ceChild.provider as cProvider "
+ "left join fetch childEvent.event as ceEvent "
+ "left join fetch ceEvent.organization as eOrganization "
+ "left join fetch eOrganization.address as oAddress "
+ "left outer join fetch ceChild.childEvent as cChildEvent "
+ "left join fetch cChildEvent.event as ceEventChildCe "
+ "left join fetch ceEventChildCe.organization as eCeOrganization "
+ "left join fetch eCeOrganization.address as oCeAddress "
+ "left outer join fetch cChildEvent.child as cCEChild "
+ "left outer join fetch cCEChild.address as address "
+ "left outer join fetch cCEChild.user as cuser "
+ "left outer join fetch cuser.address as ceaddress "
+ "left outer join fetch cCEChild.immunization as cimmunization "
+ "left outer join fetch cCEChild.insurance as cinsurance "
+ "left outer join fetch cCEChild.healthHistory as chealthHistory "
+ "left outer join fetch cCEChild.emergencyContact as cemergencyContact "
+ "left outer join fetch cCEChild.doctor as cdoctor "
+ "left outer join fetch cCEChild.dietActivityRestriction as cdietActivityRestriction "
+ "left outer join fetch cCEChild.allergy as cAllergy "
+ "left outer join fetch cCEChild.medication as cMedication "
+ "where childEvent.event.organization.organizationId = :organizationId AND (childEvent.status is null OR childEvent.status LIKE 'Active')"),
You can achieve this task by using hibernate criteria query language as follows:-
Crietria c=session.createCriteria(XYZ.class);
c.setFirstResult(1);
c.setMaxResult(500);

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