Sep 9, 2019
In the previous blog post on materialized views, we introduced a way to construct ClickHouse materialized views that compute sums and counts using the SummingMergeTree engine. The SummingMergeTree can use normal SQL syntax for both types of aggregates. We also let the materialized view definition create the underlying table for data automatically. Both of these techniques are quick but have limitations for production systems.
In the current post we will show how to create a materialized view with a range of aggregate types on an existing table.