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JPA Custom #Query aggregate boolean

I want to aggregate over a table that has a boolean column which I want to combine with a logical OR.
In plain SQL (postgres) I would write something like:
sql
SELECT t.agg_column, bool_or(t.bool_column) FROM mytable t GROUP BY t.agg_column;
How can I reflect that in a (non-native) Spring Data #Query annotation? I am looking for something on the lines of:
java
#Query("t.agg_column, bool_or(t.bool_column) FROM mytable t GROUP BY t.agg_column;")
but that doesn't work, since it doesn't know bool_or.

Spring Boot: keywords supported for JPA

I wanted to perform the Spring JPA repository where wanted to apply the and operation among 2 columns where one column cloud have multiple values in it.
SQL query for the same:
select * from table_name where col1='col1_val' and col2 IN
('col2_val_a','col2_val_b','col2_val_c');
I know that for and operation I can extend the JpaRepository and create the method with like this for:
List<MyPoJoObject> findByCol1AndCol2(String col1_val,String col2_val);
and for IN operation we can use : findByCol2In(Collection<String> col2_val)
But i did not know how i can club both the mentioned JPA default method into one, as per my sql statement mentioned before.

You can use the following method named:
List<MyPoJoObject> findByCol1AndCol2In(String col1_val, Collection<String> col2_val);
On this link repository-query-keywords you can find repository query keywords that you can use and combine them as well.

You can certainly combined both into one method.
List<MyPoJoObject> findByCol1AndCol2In(String col1_val,String[] col2_val);
Try this. I am not sure if it will accept Collection<String>. I will try that and update the answer.
HTH.

If you want to perform this logic for more than two columns then your method name becomes verbose.
Instead of stuck with Spring naming why can't you write your own JPA query.
Example:
#Query("select pojo from MyPoJoObject as pojo where pojo.col1 = :col1_val and pojo.col2 in :col2_val")
List<MyPoJoObject> findByColumns(String col1_val, List<String> col2_val);

HSQLDB: case sensitive table names

I have the following jpa/hibernate/hsqldb configuration:
JPA ddl-auto: create-drop
Hibernate entities have no #Table annotation and created with SpringPhysicalNamingStrategy. So, PersonalData entity table name is personal_data. Hibernate creates them due to running the application
hsql DB URL is jdbc:hsqldb:mem:testdb;sql.syntax_pgs=true
My problem is when I try to select due spring repositories with the hsql there is the error about non-existing PERSONAL_DATA table.
I found that this is SQL notation to use CASE_SENSETIVE tables and hqsl follows that. To resolve that developers offer quote table names in sql.
So, I have 2 unlikely ideas
Add #Table annotation to entities.
Override SpringPhysicalNamingStrategy
Is there a way to use a simple property?

Use two entity managers for one entity

The situation is the following: I have two databases Db1 and Db2, for which I have two EntityManagers em1 and em2 defined. Furthermore, I have the entity Person(int id, String name, Pet pet) mapped to the table persons(id, name) in the database Db1 and the entity Pet(int id, String name, Person owner) mapped to the table pets(id, name, person_id) in the database db2. The relation between Person and Pet is a #OneToOne realtion. At some point in the program, I would like to do something like this:
PersonDAO personDAO = db1DAOFactory.getPersonDAO();
Person person = personDAO.find(100);
System.out.println(person.getPet().getName());
There is no possibility to merge both databases. How can I tell Hibernate to use for the pet field the EntityManager em2? With Hibernate I use only annotations, no xml configuration.
Thank you very much!

Sorry but I think you can't. The question is answered by nakosspy:
Hibernate will create an SQL query for your HQL or Criteria query and this SQL will be sent through jdbc to the database. This means that hibernate does not support for what you are trying to do.
However, you can achieve the same result in some cases. Some databases give you the option to create an alias for a table that resides in a different database. So you will be able to write an SQL query that joins the two tables and execute it on the database.
We are doing that with DB2. If you can do that, it depends on your database.
I guess, that it would impossible if you have two different databases (example DB2 and MySQL) but if both databases are of the same vendor, then maybe it's achievable.
You should try to find more info in you database server's documentation.
If you want to see his original post check this link.

This is dependent on database features. If you are using Oracle database, You could achieve this by creating db link in database then map these entity through creating a view or a synonym in oracle database. Check your database features. Hope this helps.

Hibernate query build

Currently i am using the CreateSQLQuery query model to read the data from database using HIbernate. Now, I want to modify my query by using either HQL or Hibernate Criteria. My query looks like as follows.
select concat(d.AREA,' ',d.CITY) as location, a.TRANSFERRED_DATE as ActualTransferDate, concat(c.SCAN_CODE,',',c.SERIAL_NO) as ScanserialCode, c.MODEL_NO as ModelNum, c.ASSET_NAME as AssetName from table_transfer a, table_category b, table_asset c, table_location d where a.ASSET_ID = c.ASSET_ID and b.ASSET_CATEGORY_ID = c.ASSET_CATEGORY_ID and a.TRANSFER_TO_LOCATION=d.LOCATION_ID"
I am not sure how can i can convert this to Hibernate SQL or Criterion based query. Can any one help me?

You can introduce the fields for location and scanserialCode in your entity and mark them as #Formula
e.g.
#Formula("concat(d.AREA,' ',d.CITY)")
private String location;
See an example here or here
Then use join and where in HQL or Hibernate Criteria