Does marten support set operations? (Union etc)

[Abdragiz]

Tried using Union method but it didn't work.

        public class MyClass
        {
            public Guid Id { get; set; }
            public string SomeInfo { get; set; }
        }

        public static async Task Main()
        {
            CreateDatabaseIfNotExists(GetConnectionString()); // CREATE DATABASE ...
            var store = DocumentStore.For(GetConnectionString());
            using (var session = store.OpenSession())
            {
                var myClass1 = new MyClass {SomeInfo = "some info 1"};
                var myClass2 = new MyClass {SomeInfo = "some info 2"};
                session.Store(myClass1);
                session.Store(myClass2);
                await session.SaveChangesAsync();
            }

            using (var session = store.OpenSession())
            {
                var query = GetQueryable(session);
                var query1 = query.Where(obj => obj.SomeInfo == "some info 1");
                var query2 = query.Where(obj => obj.SomeInfo == "some info 2");
                var union = query1.Union(query2);
                var areQueriesCountEqual = query.Count() == union.Count(); // false
                var query1Guids = query1.Select(obj => obj.Id).ToArray();
                var unionGuids = union.Select(obj => obj.Id).ToArray();
                var areGuidsEqual = query1Guids.SequenceEqual(unionGuids); // true
                var query2HasElements = query2.Any(); // true
            }
        }


        private static IQueryable<MyClass> GetQueryable(IQuerySession session)
        {
            return session.Query<MyClass>();
        }

[jeremydmiller]

@Nadare2012 No, Marten does not support Union() queries. To be honest, I didn't realize that was a thing in Linq. The functional equivalent in Marten would be to use the batched query functionality: https://martendb.io/documentation/documents/querying/batched_queries/

And the batched queries will be more efficient in v4 FWIW.