title: Oracle query and aggregate function
body: <p>I have table name employee_1 suppose in oracle. If the mobile_no and sim_no is same i want select maximum start_date. I have tried , but no success. Please help
  The employee_1 table is below </p>
  
  <pre><code>Mobile_No   Sim_NO      Start_Date         End_Date 
  1111111111  1111111111  3/10/2017 21:02:44  10/10/2017 21:02:44
  1111111111  1111111111  11/10/2017 21:02:44 13/10/2017 21:02:44
  1111111111  1111111112  11/10/2017 21:02:44 13/10/2017 21:02:44
  1111111111  1111111111  12/10/2017 21:02:44 
  </code></pre>
  
  <p>I want to display 2 rows </p>
  
  <pre><code>1111111111  1111111111  12/10/2017 21:02:44
  1111111111  1111111112  11/10/2017 21:02:44 13/10/2017 21:02:44
  </code></pre>