I suppose that the developer would rather have the JDBC driver or database fail than failing early and maybe wrongly. Maybe a future database version supports that syntax. Apart from that, I agree that `supportsTupleDistinctCount` should be considered. It's not even used currently as far as I can tell.

Can you change the count on the query object to counting on a different column? You could for example do something like the following

if (queryObject.getModel() instanceof IdentifiableType && !((IdentifiableType) queryObject.getModel()).hasSingleIdAttribute()) {
  query.select(criteriaBuilder.countDistinct(queryObject.get("myComputedColumn")));
} else {
  query.select(criteriaBuilder.countDistinct(queryObject));
}