Filtered results by params

Question

I'm learning Rails and trying to do this the right way, but I've struggled mightily finding a solution.

I have a long list of sports rankings in my Ranking model that I'm trying to manipulate based on the filters and general business logic applied to it (i.e. date range, sport, etc).

Ranking model

t.string   "rank"
t.integer  "team_id"
t.integer  "sport_id"
t.integer  "source_id"

Team model

t.string   "team"
t.integer  "sport_id"

Sport model

t.string   "sport"

One thing I want to do, for example, is find an average of each team's rank over the years. I know one way to do this would be something like Ranking.average(:rank, :group => 'team_id'), but that doesn't seem very DRY.

Another idea I had was to create an array, hash, json, or even a temporary table (probably not a good idea) to allow me to apply calculations and manipulate the data easier.

Again, I'm still a bit green so I might be missing an easy solution but whats the best practice for this?

"that doesn't seem very DRY" - are you sure you know what DRY stands for? — Sergio Tulentsev, Jan 30 '13 at 06:24
@SergioTulentsev I know I'm probably not articulating the problem the best, it just seems like there is a better solution vs. what I'm doing. — Ryan Grush, Jan 30 '13 at 06:34

score 1 · Answer 1 · answered Jan 30 '13 at 06:27

1

This seems to be one of those cases when a developer shouldn't be afraid to drop down to raw SQL. Query Interface is nice, but sometimes you need full power.

SELECT team_id, AVG(rank)
FROM rankings
GROUP BY team_id

Use it like this:

team_ranks = ActiveRecord::Base.connection.execute(sql)

(Disclaimer: I am not very well-versed in ActiveRecord. I'm a mongodb guy. Maybe there is a built-in method for this)

answered Jan 30 '13 at 06:27

Sergio Tulentsev

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I might have to go that route (I'm more versed in SQL). Thanks for the help. – Ryan Grush Jan 30 '13 at 06:36

Filtered results by params

1 Answers1