title: How to use LINQ Group Records and use Distinct
body: <p>given this Records</p>
  <pre><code>class Record
  {
      DateTime Date {get; set;}
      string Article {get; set;}
      string Platform { get; set;}
      string Amount { get; set;}
  }
  </code></pre>
  <p>With a sql query I get a list of Records and want to Group the Platforms by Article.</p>
  <p>I do this query:</p>
  <pre><code>List&lt;Record&gt; recordList = FetchRecords();
  var group = recordList.GroupBy(
      f =&gt; f.Article, 
      (key, g) =&gt; new 
      { 
          Article= key, 
          Platforms = g.Select(p =&gt; p.Platform).ToList() 
      });
  </code></pre>
  <p>There are around 120 different Articles and about 30 different platforms, so the expected amount of items in group is around 120 yet I am recieving thousands of items. Items in record list are a lot as its the stock of all articles in the last 30 Days so I want to get a distinct list of Articles. I just can't figure out where to do this. what am I missing?</p>
  <p><strong>Edit</strong>:</p>
  <p>After further inspecting the Data at runtime I just noticed that I have it backwards. the Articles are already correctly grouped, the platforms are the ones that need to be distinct, like Astrid E was guessing in the comments</p>