From 504e44eca57601adb95b3a6d9c1fabf5e6677de4 Mon Sep 17 00:00:00 2001
From: Kalyan Kanuri <kkalyan@yahoo-inc.com>
Date: Tue, 26 Jul 2016 23:12:18 -0700
Subject: [PATCH] null check

---
 caravel/models.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/caravel/models.py b/caravel/models.py
index 444a4da6b7e13..008a3f0d820b7 100644
--- a/caravel/models.py
+++ b/caravel/models.py
@@ -1410,6 +1410,9 @@ def get_filters(raw_filters):
                         fields.append(Dimension(col) == s)
                     cond = Filter(type="or", fields=fields)
                 else:
+                    #allows setting filter to query that value of dimension is null 
+                    if eq == 'null' or eq == 'NULL':
+                        eq = None
                     cond = Dimension(col) == eq
                 if op == 'not in':
                     cond = ~cond