Apache Druid

do you mean, for each hour, you want to find the timestamp of the row that had the highest value of `VALUE` in that hour?

most natural way to write that in SQL would be something like—

```SELECT
  FLOOR(__time TO HOUR),
  MILLIS_TO_TIMESTAMP(ANY_VALUE(TIMESTAMP_TO_MILLIS(__time)))
FROM "DATASOURCE"
WHERE (FLOOR(__time TO HOUR), "VALUE") IN (
  SELECT
    FLOOR(__time TO HOUR) AS t,
    MAX("VALUE") as maxValue
  FROM "DATASOURCE"
  GROUP BY 1
)
GROUP BY 1```
you can do `EXPLAIN PLAN FOR` on that to see how it runs