I want to order by on a field known at runtime.
Following is the simplified SQL query which I'm trying to convert in Criteria Query:
SELECT
CASE
WHEN o.col2 > 0 THEN "START"
WHEN o.col2 < 0 THEN "STOP"
END AS STATUS,
o.*
FROM orders o
JOIN trade t
ON t.ID = o.t_id
WHERE t.id='1'
ORDER BY STATUS;
Following is what I've achieved so far:
CriteriaBuilder cb = getCriteriaBuilder();
CriteriaQuery<Orders> cq = cb.createQuery(Orders.class);
Root<Orders> oRoot = cq.from(Orders.class);
Join<Orders, Trade> tradeJoin = oRoot.join(Orders_.trade);
Expression<String> start = cb.literal("START");
Expression<String> stop = cb.literal("STOP");
Expression<String> statusExpr = cb.selectCase()
.when(cb.greaterThan(oRoot.get(Orders_.someCol2), 0), start)
.when(cb.lessThan(oRoot.get(Orders_.someCol2), 0), stop)
.otherwise(oRoot.get(Orders_.someCol2))
.as(String.class);
cq.multiselect(statusExpr.alias("status"), oRoot);
cq.where(cb.equal(tradeJoin.get("id"), tradeId));
//some code to fetch the sorting details
//...
cq.orderBy(cb.desc(cb.literal(sortStr)));//assume sortStr = "status"
return em.createQuery(cq).getResultList();
When I checked the query in hibernate logs, I found that the alias "status" is not getting assigned to `statusExpr` instead hibernates' autogenerated alias is getting created. This is making the above query fail by not returning the data in said order.
Any help would be appreciated.
The problem is that order by operation performed before select. At order by point in time aliases are not existed.
To order by a calculated field the query has to be like this
SELECT
CASE
WHEN o.col2 > 0 THEN "START"
WHEN o.col2 < 0 THEN "STOP"
END,
o.*
FROM orders o
JOIN trade t
ON t.ID = o.t_id
WHERE t.id='1'
ORDER BY
CASE
WHEN o.col2 > 0 THEN "START"
WHEN o.col2 < 0 THEN "STOP"
END;
So the solution
Expression<?> sortExpression;
if(sortStr.equalsIgnoreCase("status")) {
sortExpression = statusExpr;
} else {
sortExpression = oRoot.get(sortStr);
}
//...
cq.orderBy(cb.desc(sortExpression));
For multiple calculated fields you can use Map<String, Expression<?>> aliasExpressionMap = new HashMap<>(); Put calculated expressions into it and then
Expression<?> sortExpression =
aliasExpressionMap.getOrDefault(sortStr, oRoot.get(sortStr));
//...
cq.orderBy(cb.desc(sortExpression));
I'm trying to write an SQL query using CriteriaQuery, but I'm having a hard time doing so. This query basically gets a list of shipments and sorts them by their authorization date. This authorization date is represented as the date attribute of the first record in the status transition messages table with an initial status of 3 and a final status of 4. This is my query:
SELECT s.id
FROM shipment s
ORDER BY (SELECT min(stm.date)
FROM status_transition_message stm
WHERE stm.initial_status = 1 AND stm.final_status = 3 AND stm.shipment_id = s.id) desc;
I've tried multiple different solutions, but none have worked so far.
My current iteration is as follows:
private void sortByAuthDate(Root<ShipmentTbl> root, CriteriaQuery<?> query, CriteriaBuilder builder, ListSort sort) {
Subquery<Timestamp> authDateQuery = query.subquery(Timestamp.class);
Root<StatusTransitionMessageTbl> stmRoot = authDateQuery.from(StatusTransitionMessageTbl.class);
Predicate shipmentId = builder.equal(stmRoot.<ShipmentTbl>get("shipment").<String>get("id"), root.<String>get("id"));
Predicate initialStatus = builder.equal(stmRoot.<Integer>get("initialStatus"), 3);
Predicate finalStatus = builder.equal(stmRoot.<Integer>get("finalStatus"), 4);
// returns the authorization date for each queried shipment
authDateQuery.select(builder.least(stmRoot.<Timestamp>get("date")))
.where(builder.and(shipmentId, initialStatus, finalStatus));
Expression<Timestamp> authDate = authDateQuery.getSelection();
Order o = sort.getSortDirection() == ListSort.SortDirection.ASC ? builder.asc(authDate) : builder.desc(authDate);
query.multiselect(authDate).orderBy(o);
}
The problem with this solution is that the SQL query generated by the CriteriaQuery does not support subqueries in the ORDER BY clause, causing a parsing exception.
My CriteriaQuery-fu is not good enough to help you with that part, but you could rewrite your SQL query to this:
SELECT s.id
FROM shipment s
LEFT JOIN status_transition_message stm
ON stm.initial_status = 1 AND stm.final_status = 3 AND stm.shipment_id = s.id
GROUP BY s.id
ORDER BY min(stm.date) DESC;
To me, this quite likely seems to be a faster solution anyway than running a correlated subquery in the ORDER BY clause, especially on RDBMS with less sophisticated optimisers.
So I attempted to follow #Lukas Eder solution and reached this solution:
private void sortByAuthDate(Root<ShipmentTbl> root, CriteriaQuery<?> query, CriteriaBuilder builder, ShipmentListSort sort) {
Join<ShipmentTbl, StatusTransitionMessageTbl> shipmentStatuses = root.join("shipmentStatus", JoinType.LEFT);
Predicate initialStatus = builder.equal(shipmentStatuses.<Integer>get("initialStatus"), 1);
Predicate finalStatus = builder.equal(shipmentStatuses.<Integer>get("finalStatus"), 3);
Expression<Timestamp> authDate = builder.least(shipmentStatuses.<Timestamp>get("date"));
Order o = sort.getSortDirection() == ShipmentListSort.SortDirection.ASC ? builder.asc(authDate) : builder.desc(authDate);
shipmentStatuses.on(builder.and(initialStatus, finalStatus));
query.multiselect(authDate).groupBy(root.<String>get("id")).orderBy(o);
}
}
But now it's throwing this exception:
ERROR o.h.e.jdbc.spi.SqlExceptionHelper - ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list
This happens because the query is only going to get distinct shipments later on and it's asking for the sorting column also appear in the select. The problem is I don't know how to force CriteriaQuery to keep that column in the SELECT statement. It automatically only puts in the ORDER BY.
Here's the JPQL query it's executing in my test:
select
distinct generatedAlias0
from
ShipmentTbl as generatedAlias0
left join
generatedAlias0.shipmentStatus as generatedAlias1 with ( generatedAlias1.initialStatus=:param0 )
and (
generatedAlias1.finalStatus=:param1
)
where
lower(generatedAlias0.shipmentName) like :param2
group by
generatedAlias0.id
order by
min(generatedAlias1.date) desc
and the generated SQL query:
select
distinct shipmenttb0_.id as id1_13_,
shipmenttb0_.archived_date as archived2_13_,
shipmenttb0_.auth_code as auth_cod3_13_,
shipmenttb0_.authorization_date as authoriz4_13_,
shipmenttb0_.booked_in_by_user as booked_i5_13_,
shipmenttb0_.business_channel as business6_13_,
shipmenttb0_.courier as courier7_13_,
shipmenttb0_.courier_amount as courier_8_13_,
shipmenttb0_.courier_currency as courier_9_13_,
shipmenttb0_.ship_to as ship_to39_13_,
shipmenttb0_.estimated_shipment_date as estimat10_13_,
shipmenttb0_.last_updated_date as last_up11_13_,
shipmenttb0_.measurement_unit as measure12_13_,
shipmenttb0_.original_submitted_date as origina13_13_,
shipmenttb0_.packaging_type as packagi14_13_,
shipmenttb0_.placeholder_message as placeho15_13_,
shipmenttb0_.scheduled_period_of_day as schedul16_13_,
shipmenttb0_.scheduled_shipment_date as schedul17_13_,
shipmenttb0_.ship_from as ship_fr40_13_,
shipmenttb0_.ship_origin as ship_or41_13_,
shipmenttb0_.shipment_name as shipmen18_13_,
shipmenttb0_.status as status19_13_,
shipmenttb0_.submitted_date as submitt20_13_,
shipmenttb0_.supplier_contact_email as supplie21_13_,
shipmenttb0_.supplier_contact_name as supplie22_13_,
shipmenttb0_.supplier_contact_phone_number as supplie23_13_,
shipmenttb0_.supplier_email as supplie24_13_,
shipmenttb0_.supplier_secondary_contact_email as supplie25_13_,
shipmenttb0_.supplier_secondary_contact_name as supplie26_13_,
shipmenttb0_.supplier_secondary_contact_phone_number as supplie27_13_,
shipmenttb0_.tenant as tenant28_13_,
shipmenttb0_.total_received_boxes as total_r29_13_,
shipmenttb0_.total_units as total_u30_13_,
shipmenttb0_.total_value as total_v31_13_,
shipmenttb0_.total_volume as total_v32_13_,
shipmenttb0_.total_weight as total_w33_13_,
shipmenttb0_.tracking_number as trackin34_13_,
shipmenttb0_.tt_note as tt_note35_13_,
shipmenttb0_.tt_priority as tt_prio36_13_,
shipmenttb0_.updated_by_user as updated37_13_,
shipmenttb0_.weight_unit as weight_38_13_
from
shipment shipmenttb0_
left outer join
status_transition_message shipmentst1_
on shipmenttb0_.id=shipmentst1_.shipment_id
and (
shipmentst1_.initial_status=?
and shipmentst1_.final_status=?
)
where
lower(shipmenttb0_.shipment_name) like ?
group by
shipmenttb0_.id
order by
min(shipmentst1_.date) desc limit ?
I'm new using hibernate, I have query like :
select count(1) from (
SELECT COUNT (1)
FROM USR_BASE
WHERE ST_CD = 1
group by USR_NO)
How can I implement that query in Hibernate using criteria ?
Because, I already implement with method :
public int totalUser(UsrBase usrBase) {
Criteria criteria = createCriteria();
String stCd = usrBase.getStCd();
criteria.setProjection(Projections.projectionList())
.add(Projections.property("usrNo"))
.add(Projections.property(stCd))
.add(Projections.groupProperty("usrNo")));
return((Long)criteria.setProjection(Projections.rowCount()).uniqueResult()).intValue();
}
the result not same with my query... Please help me.
select count(1) from (
SELECT COUNT (1)
FROM USR_BASE
WHERE ST_CD = 1
group by USR_NO)
I think it will be more easily with
select count(distinct(USR_NO)) from USR_BASE WHERE ST_CD = 1
This feels like a trivial use case for Hibernate or JPA, but I've been struggling for a couple of days to get this to work.
I have an position entity class that has latitude, longitude and updateTime fields (among others). I would like to count the number of distinct combinations of those three fields while ignoring the others. In SQL, this is trivial:
SELECT COUNT(*) FROM (SELECT DISTINCT LONGITUDE, LATITUDE, UPDATE_TIME FROM POSITION) AS TEMP;
It is important that I abstract myh database implementation from the rest of my application because different users may wish to use different database engines. (Heck I use h2 for testing and mariadb for local production...)
I have been trying to translate this SQL into Java code using either Hibernate or JPA syntax, but I cannot figure out how.
EDIT - Here is as close as I have been able to get using JPA (ref: https://en.wikibooks.org/wiki/Java_Persistence/Criteria)
public long getCountDistinctInFlightPositions() {
Session session = sessionFactory.openSession();
CriteriaBuilder criteriaBuilder = session.getCriteriaBuilder();
CriteriaQuery<Tuple> innerQuery = criteriaBuilder.createTupleQuery();
Root<Position> position = innerQuery.from(Position.class);
innerQuery.multiselect(
position.get("longitude"),
position.get("latitude"),
position.get("updateTime")
);
// The method countDistinct(Expression<?>) in the type CriteriaBuilder is not applicable for the arguments (CriteriaQuery<Tuple>)
criteriaBuilder.countDistinct(innerQuery);
return 1;
}
You can do it this way:
CriteriaQuery<Long> countQuery = cb.createQuery( Long.class );
Root<Position> root = countQuery.from( Position.class );
countQuery.select( cb.count( root.get( "id" ) ) );
Subquery<Integer> subQuery = countQuery.subquery( Integer.class );
Root<Position> subRoot = subQuery.from( Position.class );
subQuery.select( cb.min( subRoot.get( "id" ) ) );
subQuery.groupBy( subRoot.get( "longitude" ),
subRoot.get( "latitude" ),
subRoot.get( "updateTime" ) );
countQuery.where( root.get( "id" ).in( subQuery ) );
Long count = entityManager.createQuery( countQuery ).getSingleResult();
This effectively generates the following SQL:
SELECT COUNT( p0.id ) FROM Position p0
WHERE p0.id IN (
SELECT MIN( p1.id )
FROM Position p1
GROUP BY p1.longitude, p1.latitude, p1.updateTime )
In a scenario where I have 3 rows and 2 of them have the same tuple of longitude, latitude, and update time, the query will return a result of 2.
Make sure you maintain a good index on [Longtitude, Latitude, UpdateTime] here so that you can take advantage of faster GROUP BY execution. The PK is already b-tree indexed so the other operations wrt COUNT/MIN should be accounted for easily by that index already.
I'm new to hibernate and I've this SQL query which works perfectly
SELECT count(*) as posti_disponibili from occupazione t inner join
(select id_posto_park, max(date_time) as MaxDate from occupazione
group by id_posto_park) tm on t.id_posto_park = tm.id_posto_park and
t.date_time = tm.Maxdate and t.isOccupied = 0
which gives me all the last items with isOccupied = 0
I was porting it into Hibernate, I've tried to use
result = ( (Integer) session.createSQLQuery(query).iterate().next() ).intValue()
to return posti_disponibili but i got this exception
java.lang.UnsupportedOperationException: SQL queries do not currently support iteration
How can i solve this? I cannot find the equivalent HQL query
Thank you
I would suggest you to use
Query#uniqueResult()
which will give you single result.
select count(*) .....
will always return you a single result.
Hibernate support it's own iterator-like scroll:
String sqlQuery = "select a, b, c from someTable";
ScrollableResults scroll = getSession().createSQLQuery(sqlQuery).scroll(ScrollMode.FORWARD_ONLY);
while (scroll.next()) {
Object[] row = scroll.get();
//process row columns
}
scroll.close();