带有父子记录的 Rails group_by 查询

Question

我正在尝试通过Sell Buy Create的用户

我想喜欢下面的例子

2021 (0)

2020 (0)

2019 (4)
    January (2)
        -> Buy (1) // Specifically with records date if possible
        -> Sell (1)
    
    August (1)
        -> Create (1)

    September (1)
        -> Buy (1)

2018 (3)
    January (2)
        -> Buy (1) // Specifically with records date if possible 
        -> Sell (1)
    
    August (1)
        -> Create (1)


And so on........

我正在尝试类似下面的事情

// controller 

@user = User.find(params[:user_id])
@records = @user.records.joins(:task)
.where(tasks: {name: ["Buy", "Sell", "Create"]})
.group_by {|t| t.created_at.beginning_of_year}


// view.html.erb


<% @records.each do |y, h| %>
    <%= y.strftime("%Y") %>
    <% h.each do |f| %>
        <%= f.task.name %>
    <% end %>
<% end %>

Output like below

2018 
    Buy 
    Sell

下面是我的模型和表格，我尝试了几种方法但仍然没有得到。

//table users
has_many :records, dependent: :destroy

--------------------
id | name | etc... |
--------------------
1  | john | etc    |
--------------------
2  | alex | etc    |
--------------------

//table tasks
has_many :records, dependent: :destroy

-------------
id | name   |
-------------
1  | Buy    |
-------------
2  | Sell   |
-------------
3  | Create |
-------------

//table records
belongs_to :task, required: true
belongs_to :user, required: true
    
-------------------------------------
id | user_id | task_id | created_at |
-------------------------------------
1  | 2       | 2       | timestamps |
-------------------------------------
2 | 1        | 1       | timestamps |
-------------------------------------
3 | 1        | 2       | timestamps |
-------------------------------------

提前致谢

Answer 1

而不是查询用户直接使用user_id和任务名称查询记录表，然后执行 3 group_by (s) 第一个group_by是创建任务的年份，第二个 group_by 是月份，第三个是任务名称

查找任务的代码

records = Record.joins(:user, :task).where(users: {id: @user.id}, tasks: {name: ["Buy", "Sell", "Create"]})
records_grouped_by_year = records.group_by { |e| e.created_at.year }.sort.to_h
# now you will get a list of tasks in a hash with keys as years { 2018 => [record1, record2, record3, record4]}


records_grouped_by_year_month = records_grouped_by_year.transform_values { |records| records.group_by { |r| r.created_at.strftime("%B") }) }
# now you will get a hash inside a hash first key is year second key is month the record was created in { 2018 => {"January"=>[record1, record2, record4], "August" => [record3]}

records_grouped_by_year_month_name = records_grouped_by_year_month.transform_values { |records| records.transform_values { |record| tasks.group_by { |r| r.taks.name } } }
# now you will get 3 nested hashes first key is year second key is month and third key is the record name { 2018 => {"January"=>{"Sell=>[record1, record2], "Buy=>[record4]}, "August" => { "Buy" => [record3]}}}

(records.key.first..Time.current.year).each { |year| records_grouped_by_year_month_name[year] ||= {} }
# now it will add an empty hash for each year that didn't exists in the records

在您看来：

<% task_count_grouped_by_year_grouped_by_name.each do |year, data_by_month| %>
    <h1>  <%= year %> </h1>
    <% if data_by_month.blank? %>
        <%= there was not sale on this year %>
    <% else %>
        <% data_by_month.each do |month, data_by_name| %>
            <h2>  <%= month %> </h2>
            <% data_by_name.each do |task_name, records| %>
                <br /> <bold><%= task_name %></bold> -> (<%= records.count %>) <% # 
    you have the records here as an array so you can do whatever you want with them %>
            <% end %>
        <% end %>
    <% end %>
<% end %>