I try to generate a HQL query that include user with a empty appoinment collections(mapped by OneToMany):
SELECT u FROM User u JOIN u.appointments uas WHERE u.status = 1 AND (uas.time.end < :date OR size(uas) = 0)
I tries it on several manners (NOT EXIST ELEMENT(), IS NULL
) also see: How to check if the collection is empty in NHibernate (HQL)? (This doesn't work for me)
but still not the result I want to see or some error in HQL or SQL SERVER
Note:
the query without the JOIN works:
"FROM User u WHERE u.status = 1 AND size(u.appointments) = 0"
Solved
Another JOIN solved the problem:
SELECT u FROM User u LEFT JOIN u.appointments pas1 LEFT JOIN pas1.slot t WHERE u.status = 1 AND t.end <= :date1 OR t.end IS NULL ORDER BY u.name asc
No. You have to use is null and is not null in HQL.
NVL Function - PL/HQL Reference NVL function returns first non-NULL expression.
You have to do the following: final String hql = "select app. appkey,app. type from " + getClassName() + " app where app.
Queries can use IS EMPTY operator or IS NOT EMPTY to check whether a collection association path resolves to an empty collection or has at least one value. We can use the EMPTY to check if a property is empty. The following JPQL shows how to use EMPTY to get employee withno projects.
Have you taken a look at your generated SQL? Your method works fine here:
// Hibernate query: const string hql = "from User u where u.Id = 101 and size(u.Appointments) = 0"; // Generates this working SQL: select user0_.Id as Id20_, user0_.Name as Name2_20_ from User user0_ where user0_.Id = 101 and (select count(appointment1_.Id_Solicitud) from Appointment appointment1_ where user0_.Id = appointment1_.Id_User) = 0
Using IS EMPTY
should work (I would favor a JPQL syntax):
SELECT u FROM User u WHERE u.status = 1 AND u.appointments IS EMPTY
If it doesn't, please show the generated SQL.
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