ClickHouse: Efficient way to aggregate data by different time ranges at - group-by

Question

I need to aggregate time-series data (with average functions) on different timeslots, like:
Today
last X days
Last weekend
This week
Last X weeks
This month
List item
etc...
Q1: Can it be done within GROUP BY statement or at least with a single query?
Q2: Do I need any Materialized View for that?
The table is partitioned by Month and sharded by UserID
All queries are within UserID (single shard)

Answer 1

group by with ROLLUP
create table xrollup(metric Int64, b date, v Int64 ) engine=MergeTree partition by tuple() order by tuple();
insert into xrollup values (1,'2018-01-01', 1), (1,'2018-01-02', 1), (1,'2018-02-01', 1), (1,'2017-03-01', 1);
insert into xrollup values (2,'2018-01-01', 1), (2,'2018-02-02', 1);
SELECT metric, toYear(b) y, toYYYYMM(b) m, SUM(v) AS val
FROM xrollup
GROUP BY metric, y, m with ROLLUP
ORDER BY metric, y, m
┌─metric─┬────y─┬──────m─┬─val─┐
│ 0 │ 0 │ 0 │ 6 │ overall
│ 1 │ 0 │ 0 │ 4 │ overall by metric1
│ 1 │ 2017 │ 0 │ 1 │ overall by metric1 for 2017
│ 1 │ 2017 │ 201703 │ 1 │ overall by metric1 for march 2017
│ 1 │ 2018 │ 0 │ 3 │
│ 1 │ 2018 │ 201801 │ 2 │
│ 1 │ 2018 │ 201802 │ 1 │
│ 2 │ 0 │ 0 │ 2 │
│ 2 │ 2018 │ 0 │ 2 │
│ 2 │ 2018 │ 201801 │ 1 │
│ 2 │ 2018 │ 201802 │ 1 │
└────────┴──────┴────────┴─────┘

Answer 2

Although there's an accepted answer I had to do something similar but found an alternative route using aggregate function combinators, specially -If to select specific date ranges.
I needed to group by a content ID but retrieve unique views for the whole time range and also for specific buckets to generate a histogram (ClickHouse's histogram() function wasn't suitable because there's no option for sub aggregation).
You could do something along these lines:
SELECT
group_field,
avgIf(metric, date BETWEEN toDate('2022-09-03') AND toDate('2022-09-10')) AS week_avg
avgIf(metric, date BETWEEN toDate('2022-08-10') AND toDate('2022-09-10')) AS month_avg
FROM data
GROUP BY group_field