title: How to use Union in Linq Query
body: <p>I have many tables.But there are Two columns common in each table.
  They are RegNo and Total.Now i want the values of all the total column for a particular RegNo.
  I can get that in different queries like this.</p>
  
  <pre><code>query=from k in db.MyTable1 where K.regNo=1 select k.Total
  query2=from k in db.MyTable2 where K.regNo=1 select k.Total
  </code></pre>
  
  <p>This way but i want to do this and get the Summation of all Total's Column using one single Query
  Please guide.</p>