Question

我的Transaction模型包含属性：product_id，qty和status。

我想在状态0，状态1和状态2交易的总qty的视图中显示所有产品的列表，如下所示：

| Product   | Other | buy | Sold | Balance |
--------------------------------------------
|     1     |  12   |  0  |  4   |    8    |
|     2     |  40   | 10  | 18   |   32    |
|     3     |  54   | 14  | 28   |   40    |

我查询（postgresql）上面的结果如下：

SELECT
  product_id
  ,SUM(CASE WHEN status = 0 THEN qty ELSE 0 END) AS Other
  ,SUM(CASE WHEN status = 1 THEN qty ELSE 0 END) AS Buy
  ,SUM(CASE WHEN status = 2 THEN qty ELSE 0 END) AS Sold
  ,(SUM(CASE WHEN status = 0 THEN qty ELSE 0 END) + SUM(CASE WHEN status = 1 THEN qty ELSE 0 END) - SUM(CASE WHEN status = 2 THEN qty ELSE 0 END)) AS Balance
FROM
   Transactions
GROUP BY
  product_id
ORDER BY
  product_id

检查此sqlfiddle以获取查询的测试结果。

这是我目前的代码

def index
  @transactions = Transaction.group(:product_id).select(:product_id, "SUM(qty) , :condition => ['status = ?', 0],  as other", "SUM(qty) , :condition => ['status = ?', 1],  as buy", "SUM(qty) , :condition => ['status = ?', 2],  as sold", 
    "SUM(qty) , :condition => ['status = ?', 0] + SUM(qty) , :condition => ['status = ?', 1] - SUM(qty) , :condition => ['status = ?', 2], as balance").order(:product_id).collect{ |tr| [tr.product_id, tr.other, tr.buy, tr.sold, tr.balance] }
end

和index.html.erb

<table class="data">
    <thead>
        <tr>
            <th>Product_id</th>
            <th>Other</th>
            <th>Buy</th>
            <th>Sold</th>
            <th>Balance</th>
        </tr>
    </thead>
    <tbody>
        <% if @transactions.empty? %>
           <tr>
              <td colspan="5">not found</td>
           </tr>
        <% else %>
        <% @transactions.each do |(product_id, other, buy, sold, balance), sa| %>
          <tr>
             <td><%= product_id %></td>
             <td><%= other %></td>
             <td><%= buy %></td>
             <td><%= sold %></td>
             <td><%= balance %></td>

         </tr>
       <% end %>
       <% end %>
    </tbody>
</table>

我收到此错误：

ArgumentError in TransactionsController#index

wrong number of arguments (5 for 1)

app/controllers/transactions_controller.rb:10:in `index'

有人可以纠正并帮助我，我显然已经卡住了。

具有条件轨道的多个选择总和列

0 个答案: