Rails Ransack - How to include multiple conditions with a ransacker

Question

I am trying to create a Ransack section for our search page that will look across a student's grade table and find students within a range for each kind of grade.

Given: Student has_many Grades and Grade belongs_to Category

I want a form section like: Biology Grade grater than [ 2 ] Math Grade grater than [ 3 ]

Eventually something like: SELECT... WHERE (grade.value >= 2 AND grade.category_id = 1) AND (grade.value >= 3 AND grade.category_id = 2)

Any ideas on how to set that up?

Answer 1

You need to build condition groupings. Take a look at https://github.com/activerecord-hackery/ransack/blob/master/lib/ransack/helpers/form_builder.rb#L74 and follow the code. The Ransack demo application is also a good resource.

It's a shame that Ransack does not have a comprehensive documentation. I spent a whole day trying to make similar feature work.

Try something like this:

<%= hidden_field_tag 'q[c]', 'or' %>
<% Category.each_with_index do |category, i| %>
  <%= hidden_field_tag "q[g][#{i}][m]", 'and' %>
  <%= text_field_tag "q[g][#{i}][c][0]", 'grades_value_gteq' %>
  <%= text_field_tag "q[g][#{i}][c][1]", 'grades_category_eq' %>
<% end %>

You are building groupings of conditions inside Ransack. Inside each you join the conditions with AND and then join the groups with OR.