Get records where date.year == some_year in Rails

I have a date column in my database in a Rails 3.1 app, and I want to be able to get the records where the date's year matches a specific year. I tried where(:date.year == year) but of course I got NoMethodError: undefined method 'year' for :date:Symbol. Is i开发者_JAVA技巧t possible to do this type of query?

You can use a scope to build something like:

scope :for_year, lambda {|date| where("date >= ? and date <= ?", "#{date.year}0101", "#{date.year}1231")}

In your Model:

scope :by_year, lambda { |year| where('extract(year from created_at) = ?', year) }

In your Controller:

@courses = Course.by_year(params[:year])

Jesse gave you, I think, the idea for the actual solution, but to explain why this failed - it's because it tried to evaluate ".year" as a method on the symbol you passed it: ":date".

The word :date is just a parameter to tell "where" which value it will later use to construct the SQL query to pass to the db. It doesn't turn into the actual date of the record. But the ".year" will evaluate as you're passing it as a parameter, before anything has been done with the ":date" symbol.

Assuming your date format is: YYYY-MM-DD HH:MM:SS

Try this:

where(Date.strptime(:date, "%Y-%m-%d %H:%M:%S").year == year)

OR

where(["YEAR(?) = ?", :date, year])