CODEWITHSUNDEEP
ruby-on-rails-3activerecordactive-relation
Israel
Israel

Reputation: 3412

Rails 3 query in multiple date ranges

Suppose we have some date ranges, for example:

ranges = [
          [(12.months.ago)..(8.months.ago)],
          [(7.months.ago)..(6.months.ago)],
          [(5.months.ago)..(4.months.ago)],
          [(3.months.ago)..(2.months.ago)],
          [(1.month.ago)..(15.days.ago)]
         ]

and a Post model with :created_at attribute.

I want to find posts where created_at value is in this range, so the goal is to create a query like:

SELECT * FROM posts WHERE created_at 
    BETWEEN '2011-04-06' AND '2011-08-06' OR
    BETWEEN '2011-09-06' AND '2011-10-06' OR
    BETWEEN '2011-11-06' AND '2011-12-06' OR
    BETWEEN '2012-01-06' AND '2012-02-06' OR
    BETWEEN '2012-02-06' AND '2012-03-23';

If you have only one range like this:

range = (12.months.ago)..(8.months.ago)

we can do this query:

Post.where(:created_at => range)

and query should be:

SELECT * FROM posts WHERE created_at 
    BETWEEN '2011-04-06' AND '2011-08-06';

Is there a way to make this query using a notation like this Post.where(:created_at => range)?

And what is the correct way to build this query?

Thank you

Upvotes: 5

Views: 2969

Answers (3)

amjad
amjad

Reputation: 2916

In your case, I would suggest to use mysql IN clause 

Model.where('created_at IN (?)', ranges)

Upvotes: -3

Mike Auclair
Mike Auclair

Reputation: 373

It gets a little aggressive with paren, but prepare to dive down the arel rabbit hole

ranges = [
          ((12.months.ago)..(8.months.ago)),
          ((7.months.ago)..(6.months.ago)),
          ((5.months.ago)..(4.months.ago)),
          ((3.months.ago)..(2.months.ago)),
          ((1.month.ago)..(15.days.ago))
         ]
table = Post.arel_table
query = ranges.inject(table) do |sum, range|
  condition = table[:created_at].in(range)
  sum.class == Arel::Table ? condition : sum.or(condition)
end

Then, query.to_sql should equal

(((("sessions"."created_at" BETWEEN '2011-06-05 12:23:32.442238' AND '2011-10-05 12:23:32.442575' OR "sessions"."created_at" BETWEEN '2011-11-05 12:23:32.442772' AND '2011-12-05 12:23:32.442926') OR "sessions"."created_at" BETWEEN '2012-01-05 12:23:32.443112' AND '2012-02-05 12:23:32.443266') OR "sessions"."created_at" BETWEEN '2012-03-05 12:23:32.443449' AND '2012-04-05 12:23:32.443598') OR "sessions"."created_at" BETWEEN '2012-05-05 12:23:32.443783' AND '2012-05-21 12:23:32.443938')

And you should be able to just do Post.where(query)

EDIT

You could also do something like:

range_conditions = ranges.map{|r| table[:created_at].in(r)}
query = range_conditions.inject(range_conditions.shift, &:or)

to keep it a little more terse

Upvotes: 8

Siwei
Siwei

Reputation: 21587

I suggest you try the pure string form: 

# e.g. querying those in (12.months.ago .. 8.months.ago) or in (7.months.ago .. 6.months.ago)
Post.where("(created_at <= #{12.months.ago} AND created_at >= #{8.months.ago} ) OR " + 
  "(created_at <= #{7.months.ago} AND created_at >= #{6.months.ago} )" )

Upvotes: 1

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