Question

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

Answer 1

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.

References

• Hibernate Core Reference Guide
  • 14.10. Expressions
• JPA 1.0 specification
  • Section 4.6.11 “Empty Collection Comparison Expressions”