The only way to use this feature is to specify an empty database name in Distributed table definition, but then you get a warning:

```
CREATE TABLE `demo_loan_all` (...) ENGINE=Distributed(test_cluster_two_shards_different_databases, '', demo_loan_01568, cityHash64(id));

<Warning> StorageDistributed (demo_loan_all): Name of remote database is empty. Default database will be used implicitly.
```
auto read_from_pipe = std::make_unique<ReadFromPreparedSource>(std::move(pipe));
        read_from_pipe->setStepDescription("Read from NullSource (Distributed)");
        query_plan.addStep(std::move(read_from_pipe));
        return;
    }
    const Scalars & scalars = local_context->hasQueryContext() ? local_context->getQueryContext()->getScalars() : Scalars{};
    bool has_virtual_shard_num_column = std::find(column_names.begin(), column_names.end(), "_shard_num") != column_names.end();
    if (has_virtual_shard_num_column && !isVirtualColumn("_shard_num", metadata_snapshot))
        has_virtual_shard_num_column = false;
    ClusterProxy::SelectStreamFactory select_stream_factory = remote_table_function_ptr
        ? ClusterProxy::SelectStreamFactory(
            header, processed_stage, remote_table_function_ptr, scalars, has_virtual_shard_num_column, local_context->getExternalTables())
        : ClusterProxy::SelectStreamFactory(
            header,
            processed_stage,
            StorageID{remote_database, remote_table},
            scalars,
            has_virtual_shard_num_column,
            local_context->getExternalTables());
    ClusterProxy::executeQuery(query_plan, select_stream_factory, log,
        modified_query_ast, local_context, query_info,
        sharding_key_expr, sharding_key_column_name,
        getCluster());
    
    if (!query_plan.isInitialized())
        throw Exception("Pipeline is not initialized", ErrorCodes::LOGICAL_ERROR);
}
BlockOutputStreamPtr StorageDistributed::write(const ASTPtr &, const StorageMetadataPtr & metadata_snapshot, ContextPtr local_context)
{
    auto cluster = getCluster();