diff --git a/pydrepr/drepr/outputs/array_backend/array_predicate.py b/pydrepr/drepr/outputs/array_backend/array_predicate.py
index aaf679d..64e3fdb 100644
--- a/pydrepr/drepr/outputs/array_backend/array_predicate.py
+++ b/pydrepr/drepr/outputs/array_backend/array_predicate.py
@@ -130,6 +130,13 @@ def as_ndarray(self, index_predicates: List[Union['ArrayDataPredicate', 'ArrayOb
                 index_attr_positions[j].start = min(i, index_attr_positions[j].start)
                 index_attr_positions[j].end = max(i + 1, index_attr_positions[j].end)
         data = np.transpose(data, new_axies)
+        # un-occupied dimensions should be collapse to 1 dimension (they always at the last)
+        last_un_occupied_dim = 0
+        if len(index_attr_positions) > 0:
+            last_un_occupied_dim = max((p.end for p in index_attr_positions)) + 1
+        if last_un_occupied_dim < len(data.shape) - 1:
+            shp = list(data.shape[:last_un_occupied_dim]) + [-1]
+            data = data.reshape(shp)
         return PropDataNDArray(data, attr.nodata, index_attr_positions, [a.get_data() for a in index_attrs])
 
     def o(self) -> Optional['LstArrayClass']:
diff --git a/pydrepr/drepr/version.py b/pydrepr/drepr/version.py
index e026c11..718b6fe 100644
--- a/pydrepr/drepr/version.py
+++ b/pydrepr/drepr/version.py
@@ -1,3 +1,3 @@
-__version__ = "2.9.1"   # ___PKG_VERSION___: DO NOT MODIFY the version here. Update it via version_manager.py!
+__version__ = "2.9.2"   # ___PKG_VERSION___: DO NOT MODIFY the version here. Update it via version_manager.py!
 __engine_version__ = "1.0.8"   # ___PKG_VERSION___: DO NOT MODIFY the version here. Update it via version_manager.py!
 __engine_release_tag__ = "2.7"   # ___PKG_VERSION___: DO NOT MODIFY the version here. Update it via version_manager.py!
diff --git a/pydrepr/tests/drepr/outputs/test_get_data_as_ndarray.py b/pydrepr/tests/drepr/outputs/test_get_data_as_ndarray.py
index 20a3bf3..6f7251d 100644
--- a/pydrepr/tests/drepr/outputs/test_get_data_as_ndarray.py
+++ b/pydrepr/tests/drepr/outputs/test_get_data_as_ndarray.py
@@ -45,6 +45,7 @@ def test_get_prop_as_ndarray(s01: List[BaseOutputSM], s02: List[BaseOutputSM], s
         mint_geo = sm.ns("https://mint.isi.edu/geo")
 
         for c in sm.c(mint.Variable):
+            assert c.p(rdf.value).as_ndarray([]).data.shape == (sum(1 for _ in c.iter_records()),)
             data = c.p(rdf.value).as_ndarray([c.p(mint_geo.lat), c.p(mint_geo.long)])
             assert len(data.index_props) == 2
 
@@ -68,4 +69,5 @@ def test_get_prop_as_ndarray(s01: List[BaseOutputSM], s02: List[BaseOutputSM], s
                     assert records[i].s(rdf.value) == data.data[i]
                     assert records[i].s(mint_geo.lat) == data.index_props[0][i]
                     assert records[i].s(mint_geo.long) == data.index_props[1][i]
+
     assert len(array_values) == 0 and len(graph_values) == 0
diff --git a/version_manager.py b/version_manager.py
index 01be539..f664713 100644
--- a/version_manager.py
+++ b/version_manager.py
@@ -4,7 +4,7 @@
 
 # ================================================================================
 # Note: update the version by changing variables before the `=...=` line
-DREPR_PYLIB_VESRION = "2.9.1"
+DREPR_PYLIB_VESRION = "2.9.2"
 DREPR_ENGINE_VERSION = "1.0.8"
 # this tag marks the release which contains the pre-built engine in it.
 DREPR_ENGINE_RELEASE_TAG = "2.7"