title: Codeigniter select query with AND and OR condition
body: <p>I want a Codeigniter select query from a table with three conditions in .</p>
  
  <pre><code>1. wrk_fld_exc = 140
  2. wrk_cs_sts = Open
  3. wrk_dlvrd_sts = Delivered OR wrk_cl_sts = Success
  </code></pre>
  
  <p>The third condition is an AND condition contains OR condition.
  First and second is And condition.</p>