diff --git a/bi_sql_editor/models/__init__.py b/bi_sql_editor/models/__init__.py
index e27e52a8..ef99aabc 100644
--- a/bi_sql_editor/models/__init__.py
+++ b/bi_sql_editor/models/__init__.py
@@ -2,3 +2,4 @@
 
 from . import bi_sql_view
 from . import bi_sql_view_field
+from . import ir_model
diff --git a/bi_sql_editor/models/bi_sql_view.py b/bi_sql_editor/models/bi_sql_view.py
index 3adec90e..6c5627f7 100644
--- a/bi_sql_editor/models/bi_sql_view.py
+++ b/bi_sql_editor/models/bi_sql_view.py
@@ -9,7 +9,7 @@ from psycopg2 import ProgrammingError
 
 from odoo import SUPERUSER_ID, _, api, fields, models
 from odoo.exceptions import UserError
-from odoo.tools import pycompat, sql
+from odoo.tools import pycompat, sql, table_columns
 from odoo.tools.safe_eval import safe_eval
 
 from odoo.addons.base.models.ir_model import IrModel
@@ -726,6 +726,40 @@ class BiSQLView(models.Model):
             self._log_execute(req)
             sql_view.size = self.env.cr.fetchone()[0]
 
+    def check_manual_fields(self, model):
+        # check the fields we need are defined on self, to stop it going
+        # early on install / startup - particularly problematic during upgrade
+        if "group_operator" in table_columns(
+            self.env.cr, "bi_sql_view_field"
+        ) and model._name.startswith(self._model_prefix):
+            # Use SQL instead of ORM, as ORM might not be fully initialised -
+            # we have no control over the order that fields are defined!
+            # We are not concerned about user security rules.
+            self.env.cr.execute(
+                """
+SELECT
+    f.name,
+    f.ttype,
+    f.group_operator
+FROM
+    bi_sql_view v
+    LEFT JOIN bi_sql_view_field f ON f.bi_sql_view_id = v.id
+WHERE
+    v.model_name = %s
+;
+                """,
+                (model._name,),
+            )
+            sql_fields = self.env.cr.fetchall()
+
+            for sql_field in sql_fields:
+                if (
+                    sql_field[0] in model._fields
+                    and sql_field[1] in ("integer", "float")
+                    and sql_field[2]
+                ):
+                    model._fields[sql_field[0]].group_operator = sql_field[2]
+
     def button_preview_sql_expression(self):
         self.button_validate_sql_expression()
         res = self._execute_sql_request()
diff --git a/bi_sql_editor/models/bi_sql_view_field.py b/bi_sql_editor/models/bi_sql_view_field.py
index 95cecb85..1689f7a3 100644
--- a/bi_sql_editor/models/bi_sql_view_field.py
+++ b/bi_sql_editor/models/bi_sql_view_field.py
@@ -49,6 +49,13 @@ class BiSQLViewField(models.Model):
         "timestamp without time zone": "datetime",
     }
 
+    _GROUP_OPERATOR_SELECTION = [
+        ("sum", "Sum"),
+        ("avg", "Average"),
+        ("min", "Minimum"),
+        ("max", "Maximum"),
+    ]
+
     name = fields.Char(string="Name", required=True, readonly=True)
 
     sql_type = fields.Char(
@@ -114,6 +121,13 @@ class BiSQLViewField(models.Model):
         help="For 'Many2one' Odoo field.\n" " Comodel of the field.",
     )
 
+    group_operator = fields.Selection(
+        string="Group Operator",
+        selection=_GROUP_OPERATOR_SELECTION,
+        help="By default, Odoo will sum the values when grouping. If you wish "
+        "to alter the behaviour, choose an alternate Group Operator",
+    )
+
     # Constrains Section
     @api.constrains("is_index")
     def _check_index_materialized(self):
diff --git a/bi_sql_editor/models/ir_model.py b/bi_sql_editor/models/ir_model.py
new file mode 100644
index 00000000..e3d7ed1f
--- /dev/null
+++ b/bi_sql_editor/models/ir_model.py
@@ -0,0 +1,9 @@
+from odoo import models
+
+
+class IrModelFields(models.Model):
+    _inherit = "ir.model.fields"
+
+    def _add_manual_fields(self, model):
+        super()._add_manual_fields(model)
+        self.env["bi.sql.view"].check_manual_fields(model)
diff --git a/bi_sql_editor/readme/CONTRIBUTORS.rst b/bi_sql_editor/readme/CONTRIBUTORS.rst
index 6837a2b2..1b4d1c03 100644
--- a/bi_sql_editor/readme/CONTRIBUTORS.rst
+++ b/bi_sql_editor/readme/CONTRIBUTORS.rst
@@ -1,4 +1,6 @@
 * Sylvain LE GAL (https://twitter.com/legalsylvain)
+* Richard deMeester, WilldooIT (http://www.willdooit.com/)
+* David James, WilldooIT (http://www.willdooit.com/)
 
 * This module is highly inspired by the work of
     * Onestein: (http://www.onestein.nl/)
diff --git a/bi_sql_editor/views/view_bi_sql_view.xml b/bi_sql_editor/views/view_bi_sql_view.xml
index bbbd1a0b..f2b127ee 100644
--- a/bi_sql_editor/views/view_bi_sql_view.xml
+++ b/bi_sql_editor/views/view_bi_sql_view.xml
@@ -149,6 +149,11 @@ License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
                                     <field name="name" />
                                     <field name="sql_type" />
                                     <field name="field_description" />
+                                    <field
+                                        name='group_operator'
+                                        attrs="{
+                                        'invisible': ['!', ('ttype', 'in', ('float', 'integer'))]}"
+                                    />
                                     <field
                                         name="ttype"
                                         attrs="{