CODEWITHSUNDEEP
ruby-on-railsrubyactiverecord
user3576036
user3576036

Reputation: 1435

How to fetch attribute values from a 'first' or 'last' record in Rails?

I am trying to fetch a column value of last record in Activerecord, from following.

2.2.4 :025 >   Equipment.last
  Equipment Load (1.0ms)  SELECT  `equipment`.* FROM `equipment`  ORDER BY `equipment`.`id` DESC LIMIT 1
 => #<Equipment id: 7, identifier: "LID-0000007", country_id: 99, state_id: 99, city_id: 99, listing_type: 3, title: "Mix", category_id: 1, sub_category_id: 2, manufacturer_id: 1, model: "ds323", serial_no: "232", year: 2011, condition: 4, other_condition: "", status: 4, other_status: "", price: #<BigDecimal:3d1b1d8,'0.32323E5',9(18)>, weight: nil, weight_units: nil, height: nil, height_units: nil, width: nil, width_units: nil, length: nil, length_units: nil, quantity_available: 1, name_plate_capactiy: nil, name_plate_capactiy_units: "", voltage: "", frequency: nil, phase: nil, current: "", current_units: nil, hours_worked: "", place_of_manufacturing: "", description: "", selling_status: 1, created_at: "2017-02-28 10:15:43", updated_at: "2017-02-28 10:16:30", user_id: 4, wanted_equipment_id: 5, is_read_after_active: false, slug: "mix">

I'm trying to fetch category_id of the last record.

Equipment.last.pluck(:category_id)

I think I am doing it wrong. Could somebody please tell me. How it is done?

Upvotes: 1

Views: 798

Answers (2)

DroidNoob
DroidNoob

Reputation: 1143

Your method was right. But you need to pluck :category_id first and then query the last.

Equipment.pluck(:category_id).last

This also works

Equipment.last.try(:category_id)

Upvotes: 2

Ankit Jain
Ankit Jain

Reputation: 26

I think you can use:

Equipment.last.try(:category_id)

Because last will give you single record and try will prevent you from the exception if record is not found

Upvotes: 1

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