--- a/src/pgsql_storage.py	Thu Jan 03 20:31:03 2019 +0100
+++ b/src/pgsql_storage.py	Sun Jan 06 17:29:50 2019 +0100
@@ -834,6 +834,29 @@
 
     nodeType = 'leaf'
 
+    def getOrderBy(self, ext_data, direction='DESC'):
+        """Return ORDER BY clause corresponding to Order By key in ext_data
+
+        @param ext_data (dict): extra data as used in getItems
+        @param direction (unicode): ORDER BY direction (ASC or DESC)
+        @return (unicode): ORDER BY clause to use
+        """
+        keys = ext_data.get('order_by')
+        if not keys:
+            return u'ORDER BY items.updated ' + direction
+        cols_statmnt = []
+        for key in keys:
+            if key == 'creation':
+                column = 'items.item_id'  # could work with items.created too
+            elif key == 'modification':
+                column = 'items.updated'
+            else:
+                log.msg(u"WARNING: Unknown order by key: {key}".format(key=key))
+                column = 'items.updated'
+            cols_statmnt.append(column + u' ' + direction)
+
+        return u"ORDER BY " + u",".join([col for col in cols_statmnt])
+
     def storeItems(self, item_data, publisher):
         return self.dbpool.runInteraction(self._storeItems, item_data, publisher)
 
@@ -1031,7 +1054,7 @@
 
         query.extend(query_filters)
 
-        return "ORDER BY items.updated DESC"
+        return self.getOrderBy(ext_data)
 
     def _getItems(self, cursor, authorized_groups, unrestricted, maxItems, ext_data, ids_only):
         self._checkNodeExists(cursor)
@@ -1075,7 +1098,8 @@
                     # if we have maxItems (i.e. a limit), we need to reverse order
                     # in a first query to get the right items
                     query.insert(0,"SELECT * from (")
-                    query.append("ORDER BY updated ASC LIMIT %s) as x")
+                    query.append(self.getOrderBy(ext_data, direction='ASC'))
+                    query.append("LIMIT %s) as x")
                     args.append(maxItems)
             elif rsm.after:
                 query.append("AND item_id<(SELECT item_id FROM items WHERE item=%s LIMIT 1)")