ActiveRecord find and only return selected columns

Question

edit 2 If you stumble across this  check both answers as I d now use pluck for this  I have a fairly large custom dataset that I d like to return to be echoe d out as json  One part is  l Location find row id  tmp row id  l  but I d like to do something like  l Location find row id  select  quot name  website  city quot   tmp row id  l  but this doesn t seem to be working  How would I get this to work  thx edit 1 alternatively  is there a way that I can pass an array of only the attributes I want included

User · Answer

My answer comes quite late because I m a pretty new developer  This is what you can do   Location select  name   website   city  find row id    Btw  this is Rails 4

User · Answer

pluck column name   This method is designed to perform select by a single column as direct SQL query Returns Array with values of the specified column name The values has same data type as column   Examples   Person pluck  id    SELECT people id FROM people Person uniq pluck  role    SELECT DISTINCT role FROM people Person where  confirmed   gt  true  limit 5  pluck  id    see http   api rubyonrails org classes ActiveRecord Calculations html method-i-pluck  Its introduced rails 3 2 onwards and accepts only single column  In rails 4  it accepts multiple columns

User · Answer

In Rails 2  l   Location find  id   gt  id   select   gt   name  website  city    limit   gt  1       or     l   Location find by sql  conditions   gt    SELECT name  website  city FROM locations WHERE id     LIMIT 1   id     This reference doc gives you the entire list of options you can use with  find  including how to limit by number  id  or any other arbitrary column constraint   In Rails 3 w ActiveRecord Query Interface  l   Location where   id       id   select  name  website  city   first   Ref  Active Record Query Interface  You can also swap the order of these chained calls  doing  select      where      first - all these calls do is construct the SQL query and then send it off

[ruby-on-rails] ActiveRecord find and only return selected columns

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