Proper syntax for a windowing function

Hi, all. I'm trying to figure out the proper syntax for queries such as a moving average over a window in MonetDB. THis works: sql>select avg(energy) from TABLENAME; +--------------------------+ | L3 | +==========================+ | 658.5049567388747 | +--------------------------+ This fails: select avg(energy) OVER () from TABLENAME; SELECT: function 'avg' not found (Welcome to mclient, the MonetDB/SQL interactive terminal (Jul2017-SP1) Database: MonetDB v11.27.5 (Jul2017-SP1), 'mapi:monetdb://SERVER2:50000/scada' ) How do I write such a query? Many thanks.