title: How do we check whether a column has any letters or not
body: <p>I want to use a query like:</p>
  
  <pre><code>select * from test
  </code></pre>
  
  <p>where data in the column has alphanumeric values.</p>
  
  <p>e.g. if column <code>rollno</code> has values like 20,30,40,50C,30F, then how do I find the values which have 50C and 30F types of values?</p>