diff --git a/pytools/datatable.py b/pytools/datatable.py
index 88aa522af0e56903bfdbcccd2a0ab456e2154880..5df1e0c837b2411013986ee1902f73e161dbdbb9 100644
--- a/pytools/datatable.py
+++ b/pytools/datatable.py
@@ -133,6 +133,37 @@ class DataTable:
 
         self.data.sort(mycmp, reverse=reverse)
 
+    def aggregated(self, groupby, agg_column, aggregate_func):
+        gb_indices = [self.column_indices[col] for col in groupby]
+        agg_index = self.column_indices[agg_column]
+
+        first = True
+
+        result_data = []
+
+        # to pacify pyflakes:
+        last_values = None
+        agg_values = None
+
+        for row in self.data:
+            this_values = tuple(row[i] for i in gb_indices)
+            if first or this_values != last_values:
+                if not first:
+                    result_data.append(last_values + (aggregate_func(agg_values),))
+
+                agg_values = [row[agg_index]]
+                last_values = this_values
+                first = False
+            else:
+                agg_values.append(row[agg_index])
+
+        if not first and agg_values:
+            result_data.append(this_values + (aggregate_func(agg_values),))
+
+        return DataTable(
+                [self.column_names[i] for i in gb_indices] + [agg_column],
+                result_data)
+
     def join(self, column, other_column, other_table, outer=False):
         """Return a tabled joining this and the C{other_table} on C{column}.