diff --git a/plugins/views_crosstab_table.inc b/plugins/views_crosstab_table.inc
index 5018ba1..f9c2866 100644
--- a/plugins/views_crosstab_table.inc
+++ b/plugins/views_crosstab_table.inc
@@ -335,10 +335,10 @@ class views_crosstab_table extends views_plugin_style_table {
         $crosstab_column = $result->$crosstab_columns['alias'];
         $alias = $crosstab_columns['alias']
             . '_'
-            . strtolower(preg_replace('/[^A-Za-z_]+/', '_', $crosstab_column));
+            . strtolower(preg_replace('/[^A-Za-z0-9_]+/', '_', $crosstab_column));
         // Add the new field to the query, basing it on the original data
         // query field.
-        $this->view->query->add_field(
+        $alias = $this->view->query->add_field(
             NULL, 'CASE WHEN '
             . $crosstab_columns['table']
             . '.'