diff --git a/docs/source/reference/api/eland.DataFrame.groupby.rst b/docs/source/reference/api/eland.DataFrame.groupby.rst
new file mode 100644
index 0000000..e31ce1d
--- /dev/null
+++ b/docs/source/reference/api/eland.DataFrame.groupby.rst
@@ -0,0 +1,6 @@
+eland.DataFrame.groupby
+=======================
+
+.. currentmodule:: eland
+
+.. automethod:: DataFrame.groupby
diff --git a/docs/source/reference/dataframe.rst b/docs/source/reference/dataframe.rst
index ffd9f32..cc05497 100644
--- a/docs/source/reference/dataframe.rst
+++ b/docs/source/reference/dataframe.rst
@@ -46,6 +46,7 @@ Function Application, GroupBy & Window
 
    DataFrame.agg
    DataFrame.aggregate
+   DataFrame.groupby
 
 .. _api.dataframe.stats:
 
diff --git a/eland/dataframe.py b/eland/dataframe.py
index 9829396..5eea876 100644
--- a/eland/dataframe.py
+++ b/eland/dataframe.py
@@ -1442,13 +1442,10 @@ class DataFrame(NDFrame):
         by:
             column or list of columns used to groupby
             Currently accepts column or list of columns
-            TODO Implement other combinations of by similar to pandas
 
         dropna: default True
             If True, and if group keys contain NA values, NA values together with row/column will be dropped.
-            TODO Implement False
 
-        TODO Implement remainder of pandas arguments
         Returns
         -------
         GroupByDataFrame
@@ -1495,18 +1492,18 @@ class DataFrame(NDFrame):
         [63 rows x 2 columns]
         """
         if by is None:
-            raise TypeError("by parameter should be specified to groupby")
+            raise ValueError("by parameter should be specified to groupby")
         if isinstance(by, str):
             by = [by]
         if isinstance(by, (list, tuple)):
-            remaining_columns = set(by) - set(self._query_compiler.columns)
+            remaining_columns = sorted(set(by) - set(self._query_compiler.columns))
             if remaining_columns:
                 raise KeyError(
-                    f"Requested columns {remaining_columns} not in the DataFrame."
+                    f"Requested columns {repr(remaining_columns)[1:-1]} not in the DataFrame"
                 )
 
         return GroupByDataFrame(
-            by=by, query_compiler=self._query_compiler, dropna=dropna
+            by=by, query_compiler=self._query_compiler.copy(), dropna=dropna
         )
 
     def query(self, expr) -> "DataFrame":
diff --git a/eland/field_mappings.py b/eland/field_mappings.py
index de7001a..5601827 100644
--- a/eland/field_mappings.py
+++ b/eland/field_mappings.py
@@ -64,7 +64,7 @@ ES_COMPATIBLE_TYPES: Dict[str, Set[str]] = {
 class Field(NamedTuple):
     """Holds all information on a particular field in the mapping"""
 
-    index: str
+    column: str
     es_field_name: str
     is_source: bool
     es_dtype: str
@@ -129,7 +129,7 @@ class FieldMappings:
     _mappings_capabilities: pandas.DataFrame
         A data frame summarising the capabilities of the index mapping
 
-        index                       - the eland display name
+        column (index)              - the eland display name
 
         es_field_name               - the Elasticsearch field name
         is_source                   - is top level field (i.e. not a multi-field sub-field)
@@ -537,13 +537,13 @@ class FieldMappings:
         """
 
         mapping_props = {}
-        for field_name_name, dtype in dataframe.dtypes.iteritems():
-            if es_type_overrides is not None and field_name_name in es_type_overrides:
-                es_dtype = es_type_overrides[field_name_name]
+        for column, dtype in dataframe.dtypes.iteritems():
+            if es_type_overrides is not None and column in es_type_overrides:
+                es_dtype = es_type_overrides[column]
             else:
                 es_dtype = FieldMappings._pd_dtype_to_es_dtype(dtype)
 
-            mapping_props[field_name_name] = {"type": es_dtype}
+            mapping_props[column] = {"type": es_dtype}
 
         return {"mappings": {"properties": mapping_props}}
 
@@ -708,9 +708,9 @@ class FieldMappings:
 
         """
         source_fields: List[Field] = []
-        for index, row in self._mappings_capabilities.iterrows():
+        for column, row in self._mappings_capabilities.iterrows():
             row = row.to_dict()
-            row["index"] = index
+            row["column"] = column
             source_fields.append(Field(**row))
         return source_fields
 
@@ -731,13 +731,13 @@ class FieldMappings:
         groupby_fields: Dict[str, Field] = {}
         # groupby_fields: Union[List[Field], List[None]] = [None] * len(by)
         aggregatable_fields: List[Field] = []
-        for index_name, row in self._mappings_capabilities.iterrows():
+        for column, row in self._mappings_capabilities.iterrows():
             row = row.to_dict()
-            row["index"] = index_name
-            if index_name not in by:
+            row["column"] = column
+            if column not in by:
                 aggregatable_fields.append(Field(**row))
             else:
-                groupby_fields[index_name] = Field(**row)
+                groupby_fields[column] = Field(**row)
 
         # Maintain groupby order as given input
         return [groupby_fields[column] for column in by], aggregatable_fields
diff --git a/eland/groupby.py b/eland/groupby.py
index 515d351..b9979dd 100644
--- a/eland/groupby.py
+++ b/eland/groupby.py
@@ -24,7 +24,7 @@ if TYPE_CHECKING:
 
 class GroupBy:
     """
-    This holds all the groupby base methods
+    Base class for calls to X.groupby([...])
 
     Parameters
     ----------
@@ -34,7 +34,6 @@ class GroupBy:
         Query compiler object
     dropna:
         default is true, drop None/NaT/NaN values while grouping
-
     """
 
     def __init__(
@@ -47,9 +46,8 @@ class GroupBy:
         self._dropna: bool = dropna
         self._by: List[str] = by
 
-    # numeric_only=True by default for all aggs because pandas does the same
     def mean(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["mean"],
             dropna=self._dropna,
@@ -57,7 +55,7 @@ class GroupBy:
         )
 
     def var(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["var"],
             dropna=self._dropna,
@@ -65,7 +63,7 @@ class GroupBy:
         )
 
     def std(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["std"],
             dropna=self._dropna,
@@ -73,7 +71,7 @@ class GroupBy:
         )
 
     def mad(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["mad"],
             dropna=self._dropna,
@@ -81,7 +79,7 @@ class GroupBy:
         )
 
     def median(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["median"],
             dropna=self._dropna,
@@ -89,7 +87,7 @@ class GroupBy:
         )
 
     def sum(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["sum"],
             dropna=self._dropna,
@@ -97,7 +95,7 @@ class GroupBy:
         )
 
     def min(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["min"],
             dropna=self._dropna,
@@ -105,7 +103,7 @@ class GroupBy:
         )
 
     def max(self, numeric_only: bool = True) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["max"],
             dropna=self._dropna,
@@ -113,7 +111,7 @@ class GroupBy:
         )
 
     def nunique(self) -> "pd.DataFrame":
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=["nunique"],
             dropna=self._dropna,
@@ -133,7 +131,6 @@ class GroupByDataFrame(GroupBy):
         Query compiler object
     dropna:
         default is true, drop None/NaT/NaN values while grouping
-
     """
 
     def aggregate(self, func: List[str], numeric_only: bool = False) -> "pd.DataFrame":
@@ -157,13 +154,12 @@ class GroupByDataFrame(GroupBy):
         """
         if isinstance(func, str):
             func = [func]
-        # numeric_only is by default False because pandas does the same
-        return self._query_compiler.groupby(
+        return self._query_compiler.aggs_groupby(
             by=self._by,
             pd_aggs=func,
             dropna=self._dropna,
             numeric_only=numeric_only,
-            is_agg=True,
+            is_dataframe_agg=True,
         )
 
     agg = aggregate
diff --git a/eland/operations.py b/eland/operations.py
index 4f64daa..63fcf89 100644
--- a/eland/operations.py
+++ b/eland/operations.py
@@ -271,7 +271,7 @@ class Operations:
         min    1.000205e+02        0.000000e+00   0.000000e+00               0
         """
 
-        return self._calculate_single_agg(
+        return self._unpack_metric_aggs(
             fields=fields,
             es_aggs=es_aggs,
             pd_aggs=pd_aggs,
@@ -415,7 +415,7 @@ class Operations:
         df_weights = pd.DataFrame(data=weights)
         return df_bins, df_weights
 
-    def _calculate_single_agg(
+    def _unpack_metric_aggs(
         self,
         fields: List["Field"],
         es_aggs: Union[List[str], List[Tuple[str, str]]],
@@ -425,8 +425,9 @@ class Operations:
         is_dataframe_agg: bool = False,
     ):
         """
-        This method is used to calculate single agg calculations.
-        Common for both metric aggs and groupby aggs
+        This method unpacks metric aggregations JSON response.
+        This can be called either directly on an aggs query
+        or on an individual bucket within a composite aggregation.
 
         Parameters
         ----------
@@ -533,21 +534,21 @@ class Operations:
 
             # If numeric_only is True and We only have a NaN type field then we check for empty.
             if values:
-                results[field.index] = values if len(values) > 1 else values[0]
+                results[field.column] = values if len(values) > 1 else values[0]
 
         return results
 
-    def groupby(
+    def aggs_groupby(
         self,
         query_compiler: "QueryCompiler",
         by: List[str],
         pd_aggs: List[str],
         dropna: bool = True,
-        is_agg: bool = False,
+        is_dataframe_agg: bool = False,
         numeric_only: bool = True,
     ) -> pd.DataFrame:
         """
-        This method is used to construct groupby dataframe
+        This method is used to construct groupby aggregation dataframe
 
         Parameters
         ----------
@@ -560,7 +561,7 @@ class Operations:
         dropna:
             Drop None values if True.
             TODO Not yet implemented
-        is_agg:
+        is_dataframe_agg:
             Know if groupby with aggregation or single agg is called.
         numeric_only:
             return either numeric values or NaN/NaT
@@ -574,13 +575,13 @@ class Operations:
             by=by,
             pd_aggs=pd_aggs,
             dropna=dropna,
-            is_agg=is_agg,
+            is_dataframe_agg=is_dataframe_agg,
             numeric_only=numeric_only,
         )
 
         agg_df = pd.DataFrame(results, columns=results.keys()).set_index(by)
 
-        if is_agg:
+        if is_dataframe_agg:
             # Convert header columns to MultiIndex
             agg_df.columns = pd.MultiIndex.from_product([headers, pd_aggs])
 
@@ -592,7 +593,7 @@ class Operations:
         by: List[str],
         pd_aggs: List[str],
         dropna: bool = True,
-        is_agg: bool = False,
+        is_dataframe_agg: bool = False,
         numeric_only: bool = True,
     ) -> Tuple[List[str], Dict[str, Any]]:
         """
@@ -609,8 +610,8 @@ class Operations:
         dropna:
             Drop None values if True.
             TODO Not yet implemented
-        is_agg:
-            Know if groupby aggregation or single agg is called.
+        is_dataframe_agg:
+            Know if multi aggregation or single agg is called.
         numeric_only:
             return either numeric values or NaN/NaT
 
@@ -627,13 +628,15 @@ class Operations:
                 f"Can not count field matches if size is set {size}"
             )
 
-        by, fields = query_compiler._mappings.groupby_source_fields(by=by)
+        by_fields, agg_fields = query_compiler._mappings.groupby_source_fields(by=by)
 
         # Used defaultdict to avoid initialization of columns with lists
         response: Dict[str, List[Any]] = defaultdict(list)
 
         if numeric_only:
-            fields = [field for field in fields if (field.is_numeric or field.is_bool)]
+            agg_fields = [
+                field for field in agg_fields if (field.is_numeric or field.is_bool)
+            ]
 
         body = Query(query_params.query)
 
@@ -641,11 +644,13 @@ class Operations:
         es_aggs = self._map_pd_aggs_to_es_aggs(pd_aggs)
 
         # Construct Query
-        for b in by:
+        for by_field in by_fields:
             # groupby fields will be term aggregations
-            body.term_aggs(f"groupby_{b.index}", b.index)
+            body.composite_agg_bucket_terms(
+                name=f"groupby_{by_field.column}", field=by_field.es_field_name
+            )
 
-        for field in fields:
+        for field in agg_fields:
             for es_agg in es_aggs:
                 if not field.is_es_agg_compatible(es_agg):
                     continue
@@ -665,11 +670,11 @@ class Operations:
                     )
 
         # Composite aggregation
-        body.composite_agg(
+        body.composite_agg_start(
             size=DEFAULT_PAGINATION_SIZE, name="groupby_buckets", dropna=dropna
         )
 
-        def response_generator() -> Generator[List[str], None, List[str]]:
+        def bucket_generator() -> Generator[List[str], None, List[str]]:
             """
             e.g.
             "aggregations": {
@@ -696,43 +701,51 @@ class Operations:
                     size=0,
                     body=body.to_search_body(),
                 )
+
                 # Pagination Logic
-                if "after_key" in res["aggregations"]["groupby_buckets"]:
+                composite_buckets = res["aggregations"]["groupby_buckets"]
+                if "after_key" in composite_buckets:
 
                     # yield the bucket which contains the result
-                    yield res["aggregations"]["groupby_buckets"]["buckets"]
+                    yield composite_buckets["buckets"]
 
                     body.composite_agg_after_key(
                         name="groupby_buckets",
-                        after_key=res["aggregations"]["groupby_buckets"]["after_key"],
+                        after_key=composite_buckets["after_key"],
                     )
                 else:
-                    return res["aggregations"]["groupby_buckets"]["buckets"]
+                    return composite_buckets["buckets"]
 
-        for buckets in response_generator():
+        for buckets in bucket_generator():
             # We recieve response row-wise
             for bucket in buckets:
                 # groupby columns are added to result same way they are returned
-                for b in by:
-                    response[b.index].append(bucket["key"][f"groupby_{b.index}"])
+                for by_field in by_fields:
+                    bucket_key = bucket["key"][f"groupby_{by_field.column}"]
 
-                agg_calculation = self._calculate_single_agg(
-                    fields=fields,
+                    # Datetimes always come back as integers, convert to pd.Timestamp()
+                    if by_field.is_timestamp and isinstance(bucket_key, int):
+                        bucket_key = pd.to_datetime(bucket_key, unit="ms")
+
+                    response[by_field.column].append(bucket_key)
+
+                agg_calculation = self._unpack_metric_aggs(
+                    fields=agg_fields,
                     es_aggs=es_aggs,
                     pd_aggs=pd_aggs,
                     response={"aggregations": bucket},
                     numeric_only=numeric_only,
-                    is_dataframe_agg=is_agg,
+                    is_dataframe_agg=is_dataframe_agg,
                 )
                 # Process the calculated agg values to response
                 for key, value in agg_calculation.items():
-                    if not is_agg:
-                        response[key].append(value)
+                    if isinstance(value, list):
+                        for pd_agg, val in zip(pd_aggs, value):
+                            response[f"{key}_{pd_agg}"].append(val)
                     else:
-                        for i in range(0, len(pd_aggs)):
-                            response[f"{key}_{pd_aggs[i]}"].append(value[i])
+                        response[key].append(value)
 
-        return [field.index for field in fields], response
+        return [field.column for field in agg_fields], response
 
     @staticmethod
     def _map_pd_aggs_to_es_aggs(pd_aggs):
diff --git a/eland/query.py b/eland/query.py
index 6961bd1..3c2ad1b 100644
--- a/eland/query.py
+++ b/eland/query.py
@@ -38,14 +38,17 @@ class Query:
         # type defs
         self._query: BooleanFilter
         self._aggs: Dict[str, Any]
+        self._composite_aggs: Dict[str, Any]
 
         if query is None:
             self._query = BooleanFilter()
             self._aggs = {}
+            self._composite_aggs = {}
         else:
             # Deep copy the incoming query so we can change it
             self._query = deepcopy(query._query)
             self._aggs = deepcopy(query._aggs)
+            self._composite_aggs = deepcopy(query._composite_aggs)
 
     def exists(self, field: str, must: bool = True) -> None:
         """
@@ -136,9 +139,9 @@ class Query:
         agg = {func: {"field": field}}
         self._aggs[name] = agg
 
-    def term_aggs(self, name: str, field: str) -> None:
+    def composite_agg_bucket_terms(self, name: str, field: str) -> None:
         """
-        Add term agg e.g.
+        Add terms agg for composite aggregation
 
         "aggs": {
             "name": {
@@ -148,17 +151,36 @@ class Query:
             }
         }
         """
-        agg = {"terms": {"field": field}}
-        self._aggs[name] = agg
+        self._composite_aggs[name] = {"terms": {"field": field}}
 
-    def composite_agg(
+    def composite_agg_bucket_date_histogram(
+        self,
+        name: str,
+        field: str,
+        calendar_interval: Optional[str] = None,
+        fixed_interval: Optional[str] = None,
+    ) -> None:
+        if (calendar_interval is None) == (fixed_interval is None):
+            raise ValueError(
+                "calendar_interval and fixed_interval parmaeters are mutually exclusive"
+            )
+        agg = {"field": field}
+        if calendar_interval is not None:
+            agg["calendar_interval"] = calendar_interval
+        elif fixed_interval is not None:
+            agg["fixed_interval"] = fixed_interval
+        self._composite_aggs[name] = {"date_histogram": agg}
+
+    def composite_agg_start(
         self,
         name: str,
         size: int,
         dropna: bool = True,
     ) -> None:
         """
-        Add composite aggregation e.g.
+        Start a composite aggregation. This should be called
+        after calls to composite_agg_bucket_*(), etc.
+
         https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-composite-aggregation.html
 
         "aggs": {
@@ -190,22 +212,22 @@ class Query:
 
         """
         sources: List[Dict[str, Dict[str, str]]] = []
-        aggregations: Dict[str, Dict[str, str]] = {}
 
-        for _name, agg in self._aggs.items():
-            if agg.get("terms"):
-                if not dropna:
-                    agg["terms"]["missing_bucket"] = "true"
-                sources.append({_name: agg})
-            else:
-                aggregations[_name] = agg
+        # Go through all composite source aggregations
+        # and apply dropna if needed.
+        for bucket_agg_name, bucket_agg in self._composite_aggs.items():
+            if bucket_agg.get("terms") and not dropna:
+                bucket_agg = bucket_agg.copy()
+                bucket_agg["terms"]["missing_bucket"] = "true"
+            sources.append({bucket_agg_name: bucket_agg})
+        self._composite_aggs.clear()
 
-        agg = {
+        aggs = {
             "composite": {"size": size, "sources": sources},
-            "aggregations": aggregations,
+            "aggregations": self._aggs.copy(),
         }
         self._aggs.clear()
-        self._aggs[name] = agg
+        self._aggs[name] = aggs
 
     def composite_agg_after_key(self, name: str, after_key: Dict[str, Any]) -> None:
         """
diff --git a/eland/query_compiler.py b/eland/query_compiler.py
index a40c41a..f1a4240 100644
--- a/eland/query_compiler.py
+++ b/eland/query_compiler.py
@@ -550,15 +550,22 @@ class QueryCompiler:
             self, ["nunique"], numeric_only=False
         )
 
-    def groupby(
+    def aggs_groupby(
         self,
         by: List[str],
         pd_aggs: List[str],
         dropna: bool = True,
-        is_agg: bool = False,
+        is_dataframe_agg: bool = False,
         numeric_only: bool = True,
     ) -> pd.DataFrame:
-        return self._operations.groupby(self, by, pd_aggs, dropna, is_agg, numeric_only)
+        return self._operations.aggs_groupby(
+            self,
+            by=by,
+            pd_aggs=pd_aggs,
+            dropna=dropna,
+            is_dataframe_agg=is_dataframe_agg,
+            numeric_only=numeric_only,
+        )
 
     def value_counts(self, es_size):
         return self._operations.value_counts(self, es_size)
diff --git a/eland/tests/dataframe/test_groupby_pytest.py b/eland/tests/dataframe/test_groupby_pytest.py
index a31da86..3cdd48a 100644
--- a/eland/tests/dataframe/test_groupby_pytest.py
+++ b/eland/tests/dataframe/test_groupby_pytest.py
@@ -25,13 +25,10 @@ import pandas as pd
 
 class TestGroupbyDataFrame(TestData):
     funcs = ["max", "min", "mean", "sum"]
-    extended_funcs = ["median", "mad", "var", "std"]
     filter_data = [
         "AvgTicketPrice",
         "Cancelled",
         "dayOfWeek",
-        "timestamp",
-        "DestCountry",
     ]
 
     @pytest.mark.parametrize("numeric_only", [True])
@@ -41,14 +38,29 @@ class TestGroupbyDataFrame(TestData):
         pd_flights = self.pd_flights().filter(self.filter_data)
         ed_flights = self.ed_flights().filter(self.filter_data)
 
-        pd_groupby = pd_flights.groupby("Cancelled").agg(self.funcs, numeric_only)
-        ed_groupby = ed_flights.groupby("Cancelled").agg(self.funcs, numeric_only)
+        pd_groupby = pd_flights.groupby("Cancelled").agg(
+            self.funcs, numeric_only=numeric_only
+        )
+        ed_groupby = ed_flights.groupby("Cancelled").agg(
+            self.funcs, numeric_only=numeric_only
+        )
+
+        # checking only values because dtypes are checked in aggs tests
+        assert_frame_equal(pd_groupby, ed_groupby, check_exact=False, check_dtype=False)
+
+    @pytest.mark.parametrize("pd_agg", funcs)
+    def test_groupby_aggregate_single_aggs(self, pd_agg):
+        pd_flights = self.pd_flights().filter(self.filter_data)
+        ed_flights = self.ed_flights().filter(self.filter_data)
+
+        pd_groupby = pd_flights.groupby("Cancelled").agg([pd_agg], numeric_only=True)
+        ed_groupby = ed_flights.groupby("Cancelled").agg([pd_agg], numeric_only=True)
 
         # checking only values because dtypes are checked in aggs tests
         assert_frame_equal(pd_groupby, ed_groupby, check_exact=False, check_dtype=False)
 
     @pytest.mark.parametrize("pd_agg", ["max", "min", "mean", "sum", "median"])
-    def test_groupby_aggs_true(self, pd_agg):
+    def test_groupby_aggs_numeric_only_true(self, pd_agg):
         # Pandas has numeric_only  applicable for the above aggs with groupby only.
 
         pd_flights = self.pd_flights().filter(self.filter_data)
@@ -59,7 +71,7 @@ class TestGroupbyDataFrame(TestData):
 
         # checking only values because dtypes are checked in aggs tests
         assert_frame_equal(
-            pd_groupby, ed_groupby, check_exact=False, check_dtype=False, rtol=4
+            pd_groupby, ed_groupby, check_exact=False, check_dtype=False, rtol=2
         )
 
     @pytest.mark.parametrize("pd_agg", ["mad", "var", "std"])
@@ -90,9 +102,9 @@ class TestGroupbyDataFrame(TestData):
         )
 
     @pytest.mark.parametrize("pd_agg", ["max", "min", "mean", "median"])
-    def test_groupby_aggs_false(self, pd_agg):
-        pd_flights = self.pd_flights().filter(self.filter_data)
-        ed_flights = self.ed_flights().filter(self.filter_data)
+    def test_groupby_aggs_numeric_only_false(self, pd_agg):
+        pd_flights = self.pd_flights().filter(self.filter_data + ["timestamp"])
+        ed_flights = self.ed_flights().filter(self.filter_data + ["timestamp"])
 
         # pandas numeric_only=False, matches with Eland numeric_only=None
         pd_groupby = getattr(pd_flights.groupby("Cancelled"), pd_agg)(
@@ -114,14 +126,30 @@ class TestGroupbyDataFrame(TestData):
         ed_flights = self.ed_flights().filter(self.filter_data)
 
         match = "by parameter should be specified to groupby"
-        with pytest.raises(TypeError, match=match):
+        with pytest.raises(ValueError, match=match):
             ed_flights.groupby(None).mean()
 
         by = ["ABC", "Cancelled"]
-        match = "Requested columns {'ABC'} not in the DataFrame."
+        match = "Requested columns 'ABC' not in the DataFrame"
         with pytest.raises(KeyError, match=match):
             ed_flights.groupby(by).mean()
 
+    @pytest.mark.parametrize(
+        "by",
+        ["timestamp", "dayOfWeek", "Carrier", "Cancelled", ["dayOfWeek", "Carrier"]],
+    )
+    def test_groupby_different_dtypes(self, by):
+        columns = ["dayOfWeek", "Carrier", "timestamp", "Cancelled"]
+        pd_flights = self.pd_flights_small().filter(columns)
+        ed_flights = self.ed_flights_small().filter(columns)
+
+        pd_groupby = pd_flights.groupby(by).nunique()
+        ed_groupby = ed_flights.groupby(by).nunique()
+
+        assert list(pd_groupby.index) == list(ed_groupby.index)
+        assert pd_groupby.index.dtype == ed_groupby.index.dtype
+        assert list(pd_groupby.columns) == list(ed_groupby.columns)
+
     def test_groupby_dropna(self):
         # TODO Add tests once dropna is implemeted
         pass