Rails: how can I get unique values from column

Question

How can I get unique values from column in the table? For example, I have this Products table:

ID NAME CATEGORY
1 name1 1st_cat
2 name2 2nd_cat
3 name3 1st_c         


        

Answer 1

This does all the work in the database server. The result is a simple array.

<% Product.distinct(:category).pluck(:category).each do |category|
    <%= category %>
<% end %>

Rails will generate SQL that works on any database (Postgres, MySQL, etc).

SELECT DISTINCT "products"."category" FROM "products"