From 9b9a5034ad5ece5fede6e326f44ac5f870c8e5a6 Mon Sep 17 00:00:00 2001
From: ilvalle <paolo.valleri@gmail.com>
Date: Wed, 3 Sep 2014 19:28:16 +0200
Subject: [PATCH] fix grid groupby with more than 2 Fields in the expression

---
 gluon/sqlhtml.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gluon/sqlhtml.py b/gluon/sqlhtml.py
index 5254db55..98ff1031 100644
--- a/gluon/sqlhtml.py
+++ b/gluon/sqlhtml.py
@@ -2111,6 +2111,8 @@ class SQLFORM(FORM):
                 field_id = groupby #take the field passed as groupby
             elif groupby and isinstance(groupby, Expression):
                 field_id = groupby.first #take the first groupby field
+                while not(isinstance(field_id, Field)): # Navigate to the first Field of the expression
+                    field_id = field_id.first
         table = field_id.table
         tablename = table._tablename
         if not any(str(f) == str(field_id) for f in fields):