title: SQL Server - Update Query
body: <p>I want to update one column of one table as follows:</p>
  
  <p>TB_Quest:</p>
  
  <pre><code>cod_1   cod_2   cod_3   Description  Value      Date
  -----------------------------------------------------------------
  123     181     6401    product A   7526836    19/02/2013
  123     181     6401    product B   4638607    18/02/2013
  123     181     6401    product C   9633450    06/02/2013
  789     314     1361    product 1   6218035    15/02/2013
  789     314     1361    product 2   6189032    14/02/2013
  </code></pre>
  
  <p>The result should be:</p>
  
  <pre><code>cod_1   cod_2   cod_3   Description   Value      Date
  -----------------------------------------------------------------
  123     181     6401    product A     7526836    19/02/2013
  123     181     6401    product A     4638607    18/02/2013
  123     181     6401    product A     9633450    06/02/2013
  789     314     1361    product 1     6218035    15/02/2013
  789     314     1361    product 1     6189032    14/02/2013
  </code></pre>
  
  <p>Does anyone know it?</p>
  
  <p>Thanks in advance.</p>