Question

I have the following table:

Tweet(id: integer, from_user: string, tweet_text: string, tweet_id: integer, course_id: integer, tweet_already_exists: boolean, tweet_posted_to_reviews: boolean, created_at: datetime, updated_at: datetime) 

And, for a specific course, I’d like to get the last 50 tweets, unique by user. I’ve gotten this far:

 Tweet.order("tweet_id desc").find_all_by_course_id(@course.id).first(50)

The problem with this is that if a user has tweeted more than once, they appear twice (both tweets appear) and I’d only like to get that person’s latest tweet.

Thank you!

Answer 1

It’s a bit complex, but I’m not sure it’s possible to do the query you want to do in a simpler way:

Tweet.where("tweets.updated_at >= (SELECT MAX(t.updated_at) FROM tweets AS t WHERE t.from_user=tweets.from_user)").order("tweets.tweet_id desc").find_all_by_course_id(@course.id).first(50)