Search code examples
xodus

What is the proper aproach for agregational like queries?

looking into Java query approach or Kotlin based DNQ can't see how to make queries similar to 'group by' ... What is a proper approach for such queries? E.g. when I have invoices entities and I would like to group these by company name and sum of sales.

Solution

  • Something like this can help you achieve an emulated "GROUP BY":

      entityStore.executeInTransaction(
      new StoreTransactionalExecutable() {
        @Override
        public void execute(@NotNull final StoreTransaction txn) {
          txn.getEntityTypes().forEach(type -> {
            EntityIterable result = txn.getAll(type);
            long count = result.count();
          });
        }
      });

    Essentially what this does is it queries all entity types and then do a count, similar to what GROUP BY does. From here you can just create a Map or something to put both the entity type and count in the map.