title: Kafka Stream grouping on KTable value field
body: <p>I have a use case where my KTable is like this.</p>
  
  <p><strong>KTable</strong> : orderTable</p>
  
  <p><strong>Key:Value</strong></p>
  
  <p><code>{123} :  {id1,12}</code></p>
  
  <p><code>{124} : {id2,10}</code></p>
  
  <p><code>{125} :  {id1,5}</code></p>
  
  <p><code>{126} :  {id2,11}</code></p>
  
  <p><strong>KTable</strong> : <code>orderByIdTable</code>  <code>=&gt;</code> This table would be on groupBy Value <code>field</code> <code>(id)</code> and count column value will have sum of <code>id1=(12+5)</code> , <code>id2=(10+11)</code></p>
  
  <p><strong>Key   :  Value</strong></p>
  
  <p><code>{id1}  : {17}</code></p>
  
  <p><code>{id2}  : {21}</code></p>
  
  <pre><code>         final KTable&lt;String, Order&gt; orderTable = builder.table("order-topic");
           Don't know how to do this further.....
           final KTable&lt;String,Long&gt; orderByIdTable = ?
  </code></pre>