ruby Active Record - 查找今天之前 created_at 的记录
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Active Record - Find records which were created_at before today
提问by Sayuj
I want to get all records where the created_at field is less than today (a date). Is there anything like:
我想获取 created_at 字段小于今天（日期）的所有记录。有没有类似的东西：
MyTable.find_by_created_at(< 2.days.ago)
回答by tokland
Using ActiveRecordthe standard way:
以标准方式使用ActiveRecord：
MyModel.where("created_at < ?", 2.days.ago)
Using the underlying Arelinterface:
使用底层Arel接口：
MyModel.where(MyModel.arel_table[:created_at].lt(2.days.ago))
Using a thin layerover Arel:
在 Arel 上使用薄层：
MyModel.where(MyModel[:created_at] < 2.days.ago)
Using squeel:
使用squeel：
MyModel.where { created_at < 2.days.ago }
回答by Andreas
To get all records of MyTablecreated up until 2 days ago:
要获取MyTable2 天前创建的所有记录：
MyTable.where(created_at: Date.new..2.days.ago)
Note that you can also look for records with fields containing fields in the future in similar way, i.e. to get all records of MyTablewith an event_dateat least 2 days from now:
请注意，您也可以寻找记录包含的字段在类似的方式对未来的字段，即获得的所有记录MyTable与event_date至少2天从现在开始：
MyTable.where(event_date: 2.days.from_now..DateTime::Infinity.new)
回答by 3limin4t0r
Another way is to create a scope in MyModelor in ApplicationRecordusing the Arelinterface like toklandsugensted in his answerlike so:
另一种方法是创建一个范围MyModel或ApplicationRecord使用阿雷尔一样的界面tokland在sugensted他的回答像这样：
scope :arel, ->(column, predication, *args) { where(arel_table[column].public_send(predication, *args)) }
Example usage of the scope:
范围的示例用法：
MyModel.arel(:created_at, :lt, 2.days.ago)
For all predications, check the documentationor source code. This scope doesn't break the wherechain. This means you can also do:
对于所有谓词，请检查文档或源代码。此范围不会破坏where链条。这意味着您还可以执行以下操作：
MyModel.custom_scope1.arel(:created_at, :lt, 2.days.ago).arel(:updated_at, :gt, 2.days.ago).custom_scope2
回答by Homer Jon
Time.now refers to right now or this very second. So to find all users before right now just use
Time.now 指的是现在或这一秒。所以现在要找到所有用户，只需使用
@users = User.all
This will find all users before right now and will exclude future users or users that join after Time.now
这将找到之前的所有用户，并排除未来的用户或在 Time.now 之后加入的用户
