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JOIN with multiple OR in HQL

Below is a SQL query with multiple joins and conditions which gives the desired output, I want to convert the below query to HQL
select * from customer c
join customer_geo_rel cg on c.id=cg.customer_id
join geography g on cg.geo_id=g.id
join geo_geo_hierarchy gghCluster on g.id = gghCluster.geo_id
join geo_geo_hierarchy gghDivision on gghCluster.geo_id = gghDivision.parent_geo_id
join role_data_rel rdr on gghCluster.geo_id = rdr.permission_data_id OR
gghDivision.parent_geo_id = rdr.permission_data_id OR
g.id=rdr.permission_data_id

What's the problem? HQL supports the ON clause for joins and if you use a very old version of Hibernate, you can use the WITH clause like e.g. .. join g.roleDataRelList rds on ...

Inefficient JPA query using compound Where clause

I have a tables with One-Many Relationships as follows
City->School->Teacher->Children
and my JPQL for retrieving children from a city is as below
#Query("Select c from Children c where c.teacher.school.city=:city")
Set<Children> findChildrenFromCity(#Param("city") City city);
This reference here about Where clause says that
"Compound path expressions make the where clause extremely powerful."
However, upon observing the logs I realise that the above query is doing strange things like
Generate multiple Selects instead of one Select
Some cross joins can be seen in the logs
I am trying to understand if I am defining my query correctly and if the compound Where is indeed so powerful, why is my query so inefficient.

You can use the following method:
Set<Children> findAllByTeacherSchoolCity(String city);
assuming, that your class Children has field Teacher teacher, Teacher has School school and School has String city.
In case there are differences, please ask in comments for clarification.

Try this
#Query("Select c from City city join city.schools s join s.teachers t join t.childrens c where city = :city")
Set<Children> findChildrenFromCity(#Param("city") City city);
This query is running exactly one Select query to fetch the Children entities. Check the below mentioned logs.
HIBERNATE: SELECT childrens3_.id AS id1_0_,
childrens3_.date_created AS date_cre2_0_,
childrens3_.date_updated AS date_upd3_0_,
childrens3_.NAME AS name4_0_,
childrens3_.teacher_id AS teacher_5_0_ FROM city city0_
INNER JOIN school schools1_
ON city0_.id = schools1_.city_id
INNER JOIN teacher teachers2_
ON schools1_.id = teachers2_.school_id
INNER JOIN children childrens3_
ON teachers2_.id = childrens3_.teacher_id WHERE city0_.id = ?
Now what you have is an n+1 issue. To fix such issue you can use join fetch instead of simple joins.

If you want use Query annotation try this approach
#Query("Select c from Children c join fetch c.teacher t join fetch t.school s join fetch s.city ct where ct.id = :id")

Hibernate Criteria: hibernate left join without association

I am a Hibernate newbie and i have this below query. It is working as i expected. These two tables are not associated. Is there a way to get the same result by using Criteria API or how can i run this query via Hibernate ? Any help would be appreciated.
SELECT p.title, c.content
FROM posts p
LEFT JOIN comments c ON p.id = c.post_id
WHERE p.status = 'A' AND (p.title iLIKE '%r%' OR c.content iLIKE '%r%');

Criteria API needs a path between entities, so I'm not sure this join could be done using Criteria API. Better do it with HQL if you have Hibernate >= 5.1:
select p.title, c.content
from org.example.Posts p
left outer join org.example.Comments c
on p.id = c.id
where p.status = 'A' AND (lower(p.title) LIKE '%r%' OR lower(c.content) LIKE '%r%');
Still, you could stick to using SQL queries with Hibernate or better still, create association between Posts and Comments.

HQL ERROR: Path expected for join

I keep trying variations of this query and can't seem to make this happen. I've also referenced this post: Path Expected for Join! Nhibernate Error and can't seem to apply the same logic to my query. My User object has a UserGroup collection.
I understand that the query needs to reference entities within the object, but from what I'm seeing I am...
#NamedQuery(
name = "User.findByGroupId",
query =
"SELECT u FROM UserGroup ug " +
"INNER JOIN User u WHERE ug.group_id = :groupId ORDER BY u.lastname"
)

select u from UserGroup ug inner join ug.user u
where ug.group_id = :groupId
order by u.lastname
As a named query:
#NamedQuery(
name = "User.findByGroupId",
query =
"SELECT u FROM UserGroup ug " +
"INNER JOIN ug.user u WHERE ug.group_id = :groupId ORDER BY u.lastname"
)
Use paths in the HQL statement, from one entity to the other. See the Hibernate documentation on HQL and joins for details.

You need to name the entity that holds the association to User. For example,
... INNER JOIN ug.user u ...
That's the "path" the error message is complaining about -- path from UserGroup to User entity.
Hibernate relies on declarative JOINs, for which the join condition is declared in the mapping metadata. This is why it is impossible to construct the native SQL query without having the path.

You'll be better off using where clauses. Hibernate does not accept inner joins for tables where the PK/FK relationship is not there between Entities
do
SELECT s.first_name, s.surname, sd.telephone_number FROM Student s, StudentDetails sd WHERE s.id = sd.student_id
instead of
SELECT s.first_name, s.surname, sd.telephone_number FROM Student s INNER JOIN StudentDetails sd on s.id = sd.student_id
The latter will only work if Student's id (s.id) is referenced as FK on StudentDetails (sd.student_id)) table design / erd

How use hibernate criteria for a left outer join without direct link into the two tables

I'm trying to translate a SQL quest into Hibernate criteria.
My quest is working in SQL :
select * from objective
left outer join conditionstate
on objective.conditionid = conditionstate.conditionid
and conditionstate.personid = XXXX
where objective.toto_id = YYYYY
The objective is not directly mapped to the condition_state, but into a condition.
objective --> condition <-- condition_state
I've tested something like :
final DetachedCriteria criteriaObjective =
DetachedCriteria.forClass(Objective.class);
criteriaObjective.createAlias("conditionState", "conditionState", Criteria.LEFT_JOIN);
without success..

It's hard to suggest something without seeing your actual mappings. Going by your explanation and assuming that both condition and conditionState are mapped as many-to-one, you'd write something like:
final DetachedCriteria criteriaObjective =
DetachedCriteria.forClass(Objective.class);
criteriaObjective
.createCriteria("condition", Criteria.LEFT_JOIN)
.createCriteria("conditionState", Criteria.LEFT_JOIN)
.add(Restrictions.eq("personid", "XXXX") );
criteriaObjective.add(Restrictions.eqProperty("toto_id", "YYYY") );
Note that the above is NOT equivalent to the SQL query you've provided because "personid" condition will be generated as part of "WHERE" clause. As far as I know it's impossible to do a left join with condition using Criteria API - you may need to use HQL instead which provides with keyword for that exact purpose:
select o from objective as o
left join o.condition as c
left join c.conditionState as cs
with cs.person_id = 'XXXX'
and o.toto_id = 'YYYY'