sum up amount of entries in a table in Ruby on Rails

Question

I've got a table that looks like this

I want to display the amount of entries by a certain agent. I know I can use eg

orders.sum(:demand)

to sum up the demand. (table is called orders) However, there has to be a way to sum up the entries right? Eg for agent 1, this would be 4, for agent 2 it would be 1 and for agent 3 it would be 4 entries (as can be seen in the screenshot).

Any ideas?

Answer 1

If I understood correctly, what you need is the amount of entries by :agent_id , this should work:

Order.group(:agent_id).count

And the result is

=> {1=>4, 2=>2, 3=>3}

Edit:

If what you need is the count of the current_user :

Order.where(agent_id: @current_user).count

So if current_user is '1', you get:

=> 4

Answer 2

假设“确定”，您正在向控制器发送某种请求，并指定要查询的代理...

Order.where(agent_id: params[:agent_id]).count

Answer 3

With activerecord you can use the count method for counting the results.

Order.count # => 9

With the group method you can group the results by another column.

Order.group(:agent_id) # => #<ActiveRecord::Relation [ ... ] > 

Together you can get the results you want:

Order.group(:agent_id).count # => {1: 4, 2: 2, 3: 3}