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.
```
{
    const auto & slot_to_shard = cluster->getSlotToShard();
#define CREATE_FOR_TYPE(TYPE)                                                                                       \
    if (typeid_cast<const DataType##TYPE *>(result.type.get()))                                                     \
        return createBlockSelector<TYPE>(*result.column, slot_to_shard);                                            \
    else if (auto * type_low_cardinality = typeid_cast<const DataTypeLowCardinality *>(result.type.get()))          \
        if (typeid_cast<const DataType ## TYPE *>(type_low_cardinality->getDictionaryType().get()))                 \
            return createBlockSelector<TYPE>(*result.column->convertToFullColumnIfLowCardinality(), slot_to_shard);
    CREATE_FOR_TYPE(UInt8)
    CREATE_FOR_TYPE(UInt16)
    CREATE_FOR_TYPE(UInt32)
    CREATE_FOR_TYPE(UInt64)
    CREATE_FOR_TYPE(Int8)
    CREATE_FOR_TYPE(Int16)
    CREATE_FOR_TYPE(Int32)
    CREATE_FOR_TYPE(Int64)
#undef CREATE_FOR_TYPE
    throw Exception{"Sharding key expression does not evaluate to an integer type", ErrorCodes::TYPE_MISMATCH};
}
ClusterPtr StorageDistributed::skipUnusedShards(