let dt = datetime(2017-01-29 09:00:05);
print
v1=format_datetime(dt,'yy-MM-dd [HH:mm:ss]'),
v2=format_datetime(dt, 'yyyy-M-dd [H:mm:ss]'),
v3=format_datetime(dt, 'yy-MM-dd [hh:mm:ss tt]')

// From https://learn.microsoft.com/en-us/azure/data-explorer/kusto/query/