title: Perform arithmetic in SQL
body: <p>could you please help me with this? I have the following query which returns country name, number of records for each country, and total number of countries . How can I get it to also return a column for % of each country with respect to total number. Ideal output would be something like. </p>
  
  <blockquote>
    <p>USA, 25, 100, 25% ... UK, 28, 100, 28% ... etc...</p>
  </blockquote>
  
  <pre><code>SELECT Country, COUNT(Country) AS number, (SELECT COUNT(Country) 
  FROM[Customers]) AS total FROM [Customers] 
  GROUP BY Country ORDER BY number DESC
  </code></pre>
  
  <p>I have tried <code>number/total AS percent</code> but it didn't work. Obviously I am doing something wrong.</p>
  
  <p>I want to be able to filter countries that are above certain percentage say 20%. </p>
  
  <p>Thanks!</p>