This seems harder than it should be:
I want to be able to sort a table by it's copy_count, then select only events with a unique title, and limit that query to the first 99.
Event.order("copy_count DESC").select("DISTINCT ON (events.title) *").limit(99)
ActiveRecord::StatementInvalid: PG::Error: ERROR: SELECT DISTINCT ON expressions must match initial ORDER BY expressions
For the pure SQL it will look like:
SELECT * FROM (SELECT DISTINCT ON (events.title) * FROM events ORDER BY events.title, events.copy_count DESC) top_titles ORDER BY events.copy_count DESC LIMIT 99
But i don't know, how to write it in RoR.