title: Join operation with NOSQL
body: <p>I have gone through some articles regarding Bigtable and NOSQL. It is very interesting that they avoid JOIN operations. </p>
  
  <p>As a basic example, let's take Employee and Department table and assume the data is spread across multiple tables / servers.</p>
  
  <p>Just want to know, if data is spread across multiple servers, how do we do JOIN or UNION operations?</p>