ruby-on-rails - レール関連付けに欠落している属性名

Question

Railsアプリに次のクエリがありますが、その結果には属性名がないため、amchartsで使用できません

EmployeeDepartment.joins(:states).group
("employee_departments.name").count

結果は次のとおりです。{"Academic Support":1}

このようにする方法{"department_name":"Academic Support","department_count":1}

Answer 1

次のようなハッシュがあるとします。

hash = { "Academic Support" => 1, "Another Department" => 3, "Something Else" => 4 }

map必要なものを含むハッシュの配列に変換するために使用できます。

hash.map { |k, v| { "department_name" => k, "department_count" => v } }
=> [{"department_name"=>"Academic Support", "department_count"=>1}, 
    {"department_name"=>"Another Department", "department_count"=>3}, 
    {"department_name"=>"Something Else", "department_count"=>4}] 

ハッシュにキーと値のペアが 1 つしか含まれておらず、別のハッシュが必要な場合は、次のようにします。

 Hash[[["department_name", "department_count"], hash.first].transpose]

それとももっと単純...

 { "department_name" => hash.keys.first, "department_count" => hash.values.first }

Answer 2

この手順で問題を解決しました：

次のコード:

 EmployeeDepartment.joins(:states).group
    ("employee_departments.name").count

これを生成しますrails console

 SELECT COUNT(*) AS count_all, employee_departments.name AS employee_departments_name FROM "employee_departments" INNER JOIN "tickets" ON "tickets"."employee_department_id" = "employee_departments"."id" INNER JOIN "states" ON "states"."id" = "tickets"."state_id" GROUP BY employee_departments.name

私consoleは以下で生成されたものを使用しました：

@department_count = EmployeeDepartment.find(:all,
            :select => 'employee_departments.name AS employee_departments_name, COUNT(*) AS department_counter',
            :joins => 'INNER JOIN tickets ON tickets.employee_department_id = employee_departments.id INNER JOIN states ON states.id = tickets.state_id',
            :group => 'employee_departments.name')

amcharts の結果は次のようになります。

var chartData = [{"department_counter":1,"employee_departments_name":"Academic Support"}];