work on order by began

table.cpp

@@ -21,6 +21,13 @@ ColDefNode Table::get_column_def(const std::string &col_name) {
 	}
 }
 
+ColDefNode Table::get_column_def(int col_index) {
+	if (col_index >= 0 && col_index < columns_count()) {
+		return m_col_defs[col_index];
+	} else {
+		throw Exception("column with this index does not exists (" + std::to_string(col_index) + ")");
+	}
+}
 
 Row Table::create_empty_row() {
 	return Row(columns_count());