symmetric_aggregates is a child of
symmetric_aggregates parameter determines whether or not symmetric aggregates will be applied within a given explore. When
symmetric_aggregates is on, aggregate functions return correct results, even when joins result in a fanout. Symmetric aggregates are described in more detail in this Discourse post, while the problem they solve is explained in this blog post.
By default, symmetric aggregates are turned on for every explore within Looker. This means that if your SQL dialect supports symmetric aggregates, it’s only necessary to include the
symmetric_aggregates parameter if you’d like to disable that functionality for an explore.
The following list shows which dialects support symmetric aggregates in the most recent Looker release:
Turn on symmetric aggregates for the product explore
Turn off symmetric aggregates for the customer explore
Things to Know
Create Joins Carefully When Symmetric Aggregates Are Off
Symmetric aggregates protect certain calculations from giving incorrect results when a join results in a fanout. Therefore, if your dialect does not support symmetric aggregates, or you choose to turn them off, you will need to be careful when executing joins in Looker. This problem, and the workarounds for it, are described in great detail in this blog post.