Converted index name to string to fix issue pandas-dev#15404 - BUG: to_sql errors with numeric index name - needs conversion to string

Author: redbullpeter

pandas/io/sql.py

@@ -750,7 +750,7 @@ def _get_column_names_and_types(self, dtype_mapper):
             for i, idx_label in enumerate(self.index):
                 idx_type = dtype_mapper(
                     self.frame.index.get_level_values(i))
-                column_names_and_types.append((idx_label, idx_type, True))
+                column_names_and_types.append(((text_type(idx_label)), idx_type, True))
 
         column_names_and_types += [
             (text_type(self.frame.columns[i]),