title: how to filter in xslt
body: <p>I have :</p>
  
  <pre><code>&lt;ExtData&gt;
  &lt;table&gt;
      &lt;Column biz="Bus" desc="" id="Bus" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="Bus" coreColumnDataType="TypeInt" coreColumnLength=""/&gt;
      &lt;/Column&gt;
      &lt;Column biz="ser" desc="" id="NAME" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="NAME" coreColumnDataType="TypeVarChar" /&gt;
      &lt;/Column&gt;
      &lt;Column biz="ID" desc=""  id="GLOBAL_ID" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="UCMDB_ID" coreColumnDataType="VarChar" /&gt;
          &lt;CoreColumn coreEntityName="ser_xxx" coreId="UCMDB_ID" coreColumnDataType="VarChar" /&gt;
      &lt;/Column&gt;
      &lt;Column biz="State" desc="" id="ser_STATE" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="ser_STATE" coreColumnDataType="VarChar" /&gt;
      &lt;/Column&gt;
  &lt;/table&gt;
  </code></pre>
  
  <p></p>
  
  <p>and need output >>>  filtered by atribute <code>@coreEntityName="ser"</code> :</p>
  
  <pre><code>&lt;ExtData&gt;
  &lt;table&gt;
      &lt;Column biz="Bus" desc="" id="Bus" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="Bus" coreColumnDataType="TypeInt" coreColumnLength=""/&gt;
      &lt;/Column&gt;
      &lt;Column biz="ser" desc="" id="NAME" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="NAME" coreColumnDataType="TypeVarChar" /&gt;
      &lt;/Column&gt;
      &lt;Column biz="ID" desc=""  id="GLOBAL_ID" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="UCMDB_ID" coreColumnDataType="VarChar" /&gt;
      &lt;/Column&gt;
      &lt;Column biz="State" desc="" id="ser_STATE" &gt;
          &lt;CoreColumn coreEntityName="ser" coreId="ser_STATE" coreColumnDataType="VarChar" /&gt;
      &lt;/Column&gt;
  &lt;/table&gt;
  </code></pre>
  
  <p></p>