title: Oracle: Sql to update row of the same table based on value from another row of the same table
body: <p>I need a sql to update the price column to 999 for the item records which meet the following condition:</p>
  
  <ol>
  <li>The location of the ITEM should not be null for both the records.</li>
  <li>Update the price to 999 for which one of the 2 records has location as null.</li>
  </ol>
  
  <pre> 
  ID   LOCATION   ITEM   PRICE
  1    NULL       101    0
  2    123        101    0
  3    NULL       102    0
  4    NULL       102    0
  5    124        103    0
  6    NULL       103    0
  </pre>
  
  <h2>OUTPUT TABLE SAMPLE</h2>
  
  <pre> 
  ID   LOCATION   ITEM   PRICE
  1    NULL       101    999
  2    123        101    0
  3    NULL       102    0
  4    NULL       102    0
  5    124        103    0
  6    NULL       103    999
  </pre>