I absolutely despise ActiveRecord because it makes 
    non-trivial aggregates a pain to write

I'm a SQL guy at heart.

I certainly agree with you... I loathe writing any non-trivial query in ActiveRecord's query builder.

However, I find ActiveRecord does a really good job of getting out of the way when I deem it easier to write some raw SQL.

Generally do one of two things.

If I have a really big nasty query, I'll implement it as a (standard or materialized) database view. I may query it directly or map a model to it.

Or, I'll just use `MyModel.find_by_sql("blahblahblah")` which happily accepts my handwritten SQL.

I don't have a link handy but DHH stated ages ago that the ability to do stuff like that was an explicit goal of ActiveRecord.