Single jpa #Query to return true/false when count in one table is equal to column value in other table - jpa

Question

I have 2 entities: Leaflet and Page with One to Many relation (many Pages per Leaflet)
#Entity
Leaflet {
#Id
#GeneratedValue
private UUID leafletId;
private Integer noPages;
#OneToMany(mappedBy = "leaflet", cascade = CascadeType.ALL, orphanRemoval = true)
Set<Page> pages = new HashSet<>();
}
#Entity
Page {
#Id
#GeneratedValue
private UUID pageId;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "leaflet_id")
private Leaflet leaflet;
#Enumerated
private PageStatus status = PageStatus.CREATED;
}
and status enum
public enum PageStatus {
CREATED,
FRAMED
}
I would like to write single query to return whether all Pages for given Leaflet are already FRAMED. So I wrote this
#Repository
public interface PageRepository extends JpaRepository<Page, UUID> {
#Query("SELECT case when (COUNT(p) = l.noPages) then true else false end from Page p inner join Leaflet l on p.leaflet.leafletId = l.leafletId where p.status = 1 and l.leafletId = ?1")
boolean allPagesFramed(UUID leafletId);
}
but error comes which means I cannot use l.noPages directly
ERROR: column "leaflet1_.no_pages" must appear in the GROUP BY clause or be used in an aggregate function
org.hibernate.exception.SQLGrammarException: could not extract ResultSet
Is there a way to make it 1 query ?
Of course, I can first select l.noPages with first hit to DB, then inject this value to above query (instead of join) which I'm doing right now as workaround.

Answer 1

You can do this based on page table. With nativeQuery = true
#Query(value = "select case when ( count(*) > 0 ) then false else true end " +
"from page p " +
"where p.leaflet_id = ?1 and p.status <> 1 ", nativeQuery = true)
boolean allPagesFramed(UUID leafletId);
If a page has at least one status different from 1 (FRAMED), then the query return false, not all the pages are FRAMED.