diff --git a/product/ZSQLCatalog/SQLCatalog.py b/product/ZSQLCatalog/SQLCatalog.py
index e005ec370fcacb50652caaa9ed8241d98cbd2cf4..cfe8de90ac39032317d245047f58e27acca65821 100644
--- a/product/ZSQLCatalog/SQLCatalog.py
+++ b/product/ZSQLCatalog/SQLCatalog.py
@@ -2334,7 +2334,8 @@ class Catalog(Folder,
     where_expression = ''
     select_expression = ''
     group_by_expression = ''
-
+    select_expression_key = ''
+    
     from_table_dict = {'catalog' : 'catalog'} # Always include catalog table
     if len(kw):
       if kw.has_key('select_expression_key'):