Question

I have a OneToMany relationship:

public class Class1{

    private String attr1;
    private String attr2;

    @OneToOne
    private Class2 object1;

}

public class Class2{
    private String attr3;    
}

The relationship can store null objects (I mean that an instance of Class1 can have null in object1). I want to do a complete search in all attributes so I’ve created this HQL query:

SELECT p FROM Class1 p
WHERE 
(
upper(p.attr1) LIKE :filter OR
upper(p.attr2) LIKE :filter OR
upper(p.object1.attr3) LIKE :filter
)

and I pass a String param in uppercase with “%” before and after:

query.setParameter("filter", "%"+filter.trim().toUpperCase()+"%");

It works OK but for the entities which have object1 = null. It never get those entities. Indeed if I remove the last condition (upper(p.object1.attr3) LIKE :filter) it works but I need to include it.

I’ve though I should do a LEFT JOIN with that relationship so I’ve tried to write it as :

SELECT p FROM Class1 p LEFT JOIN p.object1 AS p1
WHERE 
(
upper(p.attr1) LIKE :filter OR
upper(p.attr2) LIKE :filter OR
upper(p1.attr3) LIKE :filter
)

or like

SELECT p FROM Class1 p LEFT JOIN p.object1 AS p1
WHERE 
(
upper(p.attr1) LIKE :filter OR
upper(p.attr2) LIKE :filter OR
(p1 is not null AND upper(p1.attr3) LIKE :filter)
)

but without any success.

Any idea?

Thanks.

Answer 1

As I understand you need the values either p1.attr3 is null and when it is not null it should validate the condition. So, I am just fine tuning your last query;

SELECT p FROM Class1 p LEFT JOIN p.object1 AS p1
WHERE 
(
upper(p.attr1) LIKE :filter OR
upper(p.attr2) LIKE :filter OR
(p1.attr3 is null OR upper(p1.attr3) LIKE :filter)
)