title: How to update a field in two identical column
body: <p>I'm new to Oracle. I have created a below table</p>
  
  <pre><code>SQL&gt; select * from t12;
  
    COL1      COL2                 COL3
  ---------- -------------------- ---------
       5      Social               15-OCT-90
       7      Chemistry            17-OCT-90
       7      Chemistry            17-OCT-90
  </code></pre>
  
  <p>2nd and 3rd row are identical. how can i update only 3rd row,col1 on this table?</p>