It's rather easy and well documented how to compact the data in clickhouse after TTL, for example from the docs...

CREATE TABLE events
(
    `event` String,
    `time` DateTime,
    `value` UInt64
)
ENGINE = MergeTree
ORDER BY (toDate(time), event)
TTL time + INTERVAL 1 MONTH GROUP BY toDate(time), event SET value = SUM(value)

What I currently fail to grasp is how to compact it down to two rows, instead of one. For example let's say I have only dates and values and want the min and max for the day here instead of the sum. So, for example...