ruby-on-rails - Rails 关联中缺少属性名称

Question

我的 rails 应用程序中有以下查询，但其结果没有属性名称，因此我无法在 amcharts 中使用它

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

结果是：{"Academic Support":1}

如何使它像这样{"department_name":"Academic Support","department_count":1}

Answer 1

假设你有一个这样的哈希：

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

您可以使用map将其转换为包含所需内容的哈希数组。

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}] 

如果您的散列只包含一个键/值对，而您只想要另一个散列，您可以试试这个：

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

或者更简单...

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

Answer 2

我通过以下步骤解决了我的问题：

以下代码：

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

生成这个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

我使用了console以下内容中生成的内容：

@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')

现在 amcharts 中的结果是：

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