bottomline.md

• By default rails will set the current utc time for created_at and rails will display them by converting into the application timeone

• You can set application time zone with config.time_zone = 'Eastern Time (US & Canada)'

• You can set application time zone config.active_record.default_timezone = :utc Supports :utc and :local

• Use Time.current wherever possible

• This doesn't work as expected

  Message.where(created_at: '19/01/2018'.to_time.beginning_of_day..'19/01/2018'.to_time.end_of_day)
  Message Exists (0.2ms)  SELECT  1 AS one FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?) LIMIT ?  [["created_at", "2018-01-18 18:30:00"], ["created_at", "2018-01-19 18:29:59.999999"], ["LIMIT", 1]]
  Message Load (0.1ms)  SELECT "messages".* FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?)  [["created_at", "2018-01-18 18:30:00"], ["created_at", "2018-01-19 18:29:59.999999"]]

• Whereas this does

  Message.where(created_at: '19/01/2018'.to_time.in_time_zone.beginning_of_day..'19/01/2018'.to_time.in_time_zone.end_of_day)
  Message Exists (0.3ms)  SELECT  1 AS one FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?) LIMIT ?  [["created_at", "2018-01-18 05:00:00"], ["created_at", "2018-01-19 04:59:59.999999"], ["LIMIT", 1]]
  Message Load (0.1ms)  SELECT "messages".* FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?)  [["created_at", "2018-01-18 05:00:00"], ["created_at", "2018-01-19 04:59:59.999999"]]

• Query differences

  2.4.3 :008 > Message.where(created_at: '2018-01-19 00:00:00'.to_time..'2018-01-19 23:59:59'.to_time)
  Message Exists (0.2ms)  SELECT  1 AS one FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?) LIMIT ?  [["created_at", "2018-01-18 18:30:00"], ["created_at", "2018-01-19 18:29:59"], ["LIMIT", 1]]
  Message Load (0.1ms)  SELECT "messages".* FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?)  [["created_at", "2018-01-18 18:30:00"], ["created_at", "2018-01-19 18:29:59"]]
  
  2.4.3 :007 > Message.where(created_at: '2018-01-19 00:00:00'..'2018-01-19 23:59:59')
  Message Exists (0.4ms)  SELECT  1 AS one FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?) LIMIT ?  [["created_at", "2018-01-19 00:00:00"], ["created_at", "2018-01-19 23:59:59"], ["LIMIT", 1]]
  Message Load (0.2ms)  SELECT "messages".* FROM "messages" WHERE ("messages"."created_at" BETWEEN ? AND ?)  [["created_at", "2018-01-19 00:00:00"], ["created_at", "2018-01-19 23:59:59"]]