How to specify a less than today condition on a date in rails active record

问题

I'm trying to figure out how to pull all the records in my set where their fields "publish" is true and "expires" is less than today. I have the following but i dont think the less than part is working, can someone please point me on the right track?

  @announcements = Announcement.where(:publish => true, :expires < Date.today)

Thanks in advance for your help

回答1:

Try this:

@announcements = Announcement.where("publish = ? AND expires < ?", true, Date.today)

回答2:

Since this comes up first on google I thought I'd chime in. It's probably better to rely on Arel in this circumstance.

expires = Announcement.arel_table[:expires]
@announcements = Announcement.where(:publish => true)
  .where(expires.lt(Date.today))

That will build the following SQL query

-- Using Arel
SELECT "announcements".* FROM "announcements" 
WHERE "announcements"."publish" = 't' 
  AND ("announcements"."expires" < '2016-02-03 18:41:26.454325')

-- Contrast that with the string binding method mentioned above
SELECT "announcements".* FROM "announcements"
WHERE (publish = 't' AND expires < '2016-02-03 18:41:26.454325')

The column names are fully qualified, so you will avoid conflicts when composing other queries on top of this ActiveRecord::Relation i.e @announcements

来源：https://stackoverflow.com/questions/8457902/how-to-specify-a-less-than-today-condition-on-a-date-in-rails-active-record