title: oracle query returns 0 records when args passed
body: <p>When I run an sql like this:</p>
  
  <pre><code>select * from tbl_emp where emp_name like '%%'
  </code></pre>
  
  <p>It gives me all records.
  When I run it like this:</p>
  
  <pre><code>select * from tbl_emp where emp_name like : arg_emp_name
  </code></pre>
  
  <p>Then execute the query, then pass arg_emp_name as <code>'%%'</code>, it returns 0 records.
  Why is this behavior?
  Thank you.</p>