title: sql server sql query
body: <p>in my application user can give username or emailid to login how can i write the query like</p>
  
  <pre><code>select username,password from employee
  where username='xxxx' or 'xxxx@yahoo.com' and password='******' 
  </code></pre>
  
  <p>how can i write the query so that user can give username or emailid to login.
  please send query for this problem thank u</p>