Получит ли это желаемый результат?
(с использованием arg_max (): https://docs.microsoft.com/en-us/azure/kusto/query/arg-max-aggfunction)
let Metadata = datatable(deviceID:string, appName:string, appVersion:string, timeZone:string, dateTimeUtc:datetime)
[
"d1", "a1", "v1", "PST", datetime(2018-12-01 15:53),
"d1", "a2", "v2", "PST", datetime(2018-12-01 12:01),
"d1", "a1", "v3", "UTC", datetime(2018-12-03 16:47:22),
"d1", "a2", "v4", "PST", datetime(2018-12-03 14:34:22),
"d2", "a2", "v2", "UTC", datetime(2018-11-30 15:54:22),
"d2", "a1", "v3", "PST", datetime(2018-11-30 14:53:22),
"d2", "a2", "v4", "UTC", datetime(2018-12-01 15:52:22),
"d2", "a1", "v1", "PST", datetime(2018-12-01 12:51:22)
];
Metadata
| where dateTimeUtc > ago(30d)
| summarize arg_max(dateTimeUtc, *) by deviceID, startofday(dateTimeUtc)
| project-away dateTimeUtc1