Do you need to edit the data or just display only? If just display, you should take at look at the local array data source example.
1.Return array from MySQL stored procedure, see this example:
http://php.net/manual/en/mysqli.quickstart.stored-procedures.php,
2.Then use the phpGrid local array feature to display datagrid
http://phpgrid.com/example/local_array_data_source/
That's it!