title: select random ~100 million rows of billions
body: <p>I'm a little compute-constrained because I don't want to kill the database or bandwidth while pulling for hours.</p>
  
  <p>my current query is something like this:    </p>
  
  <pre><code>SELECT TOP (100000000) mycolumns
  FROM mydb
  WHERE lower_control_limit&gt; value1
      AND upper_control_limit &lt; value2 ;
  </code></pre>
  
  <p>I am not getting a decent random sample, but I am afraid of putting commands that have to traverse billions of rows before returning values.  I need a uniform random sample over the domain (rows).</p>
  
  <p>What is the "best practice" for pulling a few hundred million rows from a store that is many billions of rows in size?</p>
  
  <p>I've seen the random, but I'm just worried about the size of the query vs. limited computing and bandwidth resources. </p>