title: LINQ on datatable to sum multiple columns vb.net
body: <p>Does anyone know if it is possible to sum multiple columns of a datatable or datagridview, based on a given criteria for another column? in short I have a table that looks (simply) like this:</p>
  
  <pre><code>Ph Length  Start
  A     10     1.5
  B     14     2
  C     9      1.8
  A     11     1.4
  </code></pre>
  
  <p>and so on....</p>
  
  <p>What I would like to do is understand is, is it possible to use LINQ to sum based on the "Ph" for both the length and Start columns in one query? Or do I need to write one for each letter?</p>
  
  <p>Essentially the result would need to be A = 21, 2.9. B = 14, 2. C = 9, 1.8</p>
  
  <p>I am stumped here and I honestly have no idea how to do this. I do not even mind if someone could point me to a really good resource for learning LINQ better.</p>