Reputation:

How to find a record created on the previous month?

I have a table where new records are added daily. How would I go about finding records created in the previous month?

Upvotes: 11

Answers (11)

Gabriel Zanatto Salami

Reputation: 1

You can use this:

last_month = Time.zone.today.last_month # considering time zones
Thing.where(created_at: last_month.all_month)

Upvotes: 0

webaholik

Reputation: 1795

Try this for Rails 4+, note that Date.current will use your application's timezone (specified in application.rb):

scope :created_last_month, lambda {
  where(created_at: Date.current.last_month.beginning_of_month..Date.current.last_month.end_of_month)
}

Upvotes: 1

B Seven

Reputation: 45943

The accepted answer and lambda improvement do not work in Rails 4.

Update for Rails 4:

scope :last_month, -> {
    where( 'created_at > ? AND created_at < ?', 
            Date.today.last_month.beginning_of_month, 
            Date.today.beginning_of_month )}

Upvotes: 5

Syed

Reputation: 16513

In one of my projects i used this way:

Thing.where('created_at BETWEEN ? AND ? ', DateTime.now.beginning_of_month - 1.month, DateTime.now.beginning_of_month)

in Rails 3 using last_month throws an error: Date.today.last_month.beginning_of_month

NoMethodError: undefined method `last_month'

Upvotes: 1

joshnuss

Reputation: 231

this is a good candidate for SQL's BETWEEN syntax

named_scope :last_month, :conditions => ['created_at BETWEEN ? AND ?', Date.today.last_month.beginning_of_month, Date.today.beginning_of_month])

Upvotes: 0

Ian Terrell

Reputation: 10866

The named_scope is a rather elegant way to go, I think, but if you take that route you will want to use it with a lambda method so that the time doesn't get scoped to when the application is initially loaded.

For example, this:

named_scope :last_month, :conditions => 
  ['created_at > ? AND created_at < ?', 
  Date.today.last_month.beginning_of_month, Date.today.beginning_of_month]

will work properly the first month your application is up, but improperly the next month, unless the app gets restarted.

But this:

named_scope :last_month, lambda {
  {:conditions => ['created_at > ? AND created_at < ?', 
   Date.today.last_month.beginning_of_month, Date.today.beginning_of_month]}}

will work every time, because the lambda method gets executed on every call, reevaluating the Date.todays.

Upvotes: 11

meh

Reputation:

Thanks everyone, I ended up going with this:

find(:all, :conditions => ['created_at > ? AND created_at < ?', Date.today.last_month.beginning_of_month, Date.today.beginning_of_month])

Upvotes: 1

August Lilleaas

Reputation: 54593

Thing.find(:all, :conditions => ["created_at > ?", 1.month.ago.at_beginning_of_month])

Upvotes: 0

Andrew Vit

Reputation: 19239

Set up a named scope:

named_scope :in_last_month, :conditions => [ "records.created_at > ?", 1.month.ago ]

To call it (in your controller):

Record.in_last_month

Upvotes: 11

Chuck

Reputation: 237010

Assuming your records are timestamped, you can just do something like this:

Thing.find(:all, :conditions => ["created_at > ?", Time.now - 1.month])

If they're not timestamped, you should start storing the information since it's something you'll want to look up later.

Upvotes: 3

Keltia

Reputation: 14743

Do you have the "usual" fields on your table? See the RoR wiki for a list of them. That way, you can express special queries to find an answer.

Upvotes: 0

How to find a record created on the previous month?

Answers (11)

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