diff --git a/product/ZSQLCatalog/Query/SimpleQuery.py b/product/ZSQLCatalog/Query/SimpleQuery.py
index d50326659025e794101f65255d5244cb45479282..20f498ea07417c385c00d349c9714862ffacb12a 100644
--- a/product/ZSQLCatalog/Query/SimpleQuery.py
+++ b/product/ZSQLCatalog/Query/SimpleQuery.py
@@ -140,6 +140,8 @@ class SimpleQuery(QueryMixin):
       search_key_class = DefaultKey
     elif isinstance(value, float):
       search_key_class = FloatKey
+    elif value is None:
+      return RawKey
     return search_key_class
 
   def _asSQLExpression(self, search_key_class, key, value, format=None, mode=None, range_value=None, stat__=None):
diff --git a/product/ZSQLCatalog/SearchKey/RawKey.py b/product/ZSQLCatalog/SearchKey/RawKey.py
index dd464c68807d7cfacad9d91fba4c05649539d59d..064bf7c4b45aa1fc328ac4669eb178a1f4532891 100644
--- a/product/ZSQLCatalog/SearchKey/RawKey.py
+++ b/product/ZSQLCatalog/SearchKey/RawKey.py
@@ -39,5 +39,8 @@ class RawKey(SearchKey):
 
   def buildSQLExpression(self, key, value, 
                          format=None, mode=None, range_value=None, stat__=None):
-    where_expression = "%s = '%s'" %(key, value)
+    if value is not None:
+      where_expression = "%s = '%s'" % (key, value)
+    else:
+      where_expression = "%s is NULL" % (key)
     return where_expression, []
diff --git a/product/ZSQLCatalog/tests/testSearchKeys.py b/product/ZSQLCatalog/tests/testSearchKeys.py
index df504f4aa783503fcdbfbacea5bbc270c0e98250..e75ff300ad4733c596f1278135216807833cc5e5 100644
--- a/product/ZSQLCatalog/tests/testSearchKeys.py
+++ b/product/ZSQLCatalog/tests/testSearchKeys.py
@@ -374,7 +374,12 @@ class TestSearchKeyQuery(unittest.TestCase):
                  '.',
                  "delivery.stock = '.'",
                  [])
-                
+    #None values
+    self.compare(RawKey,
+                 'title',
+                 None,
+                 "title is NULL",
+                 [])
   def test_06FullTextKey(self, quiet=quiet, run=run_all_test):
     """ Check FullTextKey query generation"""
     if not run: return