title: Convert text blob to nvarchar from Firebird to SQL Server
body: <p>I am using <code>SQL Server</code> and have got a <code>Firebird</code> database as a linked server in my SQL Server.</p>
  
  <p>I am trying to do an <code>OPENQUERY</code> to import data from the <code>Firebird</code> db;</p>
  
  <pre><code>SELECT * FROM OPENQUERY(Workbench, 'SELECT * FROM table_name')
  </code></pre>
  
  <p>and am getting the following error.</p>
  
  <pre><code>OLE DB provider "MSDASQL" for linked server "Workbench" returned message "Requested conversion is not supported.".
  Msg 7341, Level 16, State 2, Line 4
  Cannot get the current row value of column "[MSDASQL].NOTES" from OLE DB provider "MSDASQL" for linked server "Workbench". 
  </code></pre>
  
  <p>The data type <code>NOTES</code> field in the <code>Firebird</code> db is <code>blob</code>. If  I omit the field <code>NOTES</code> the query executes and the results are imported correct.</p>
  
  <p>But I need the information in the <code>NOTES</code> field and am looking for a way to <code>type cast</code> the blob field to <code>nvarchar</code>. I believe that this should be done within the <code>Openquery</code> (i.e. in the Firebird side of the query).</p>
  
  <p>Could somebody suggest a pure <code>SQL</code> solution to convert <code>blob</code> to <code>nvarchar</code> in <code>Firebird</code> Please?</p>