SQL :Varchar invalid for Sum operator
<p>I use this code trying to get sum of 4,202 &amp; 203 but it return me error</p>

<pre><code>SELECT *
FROM
( SELECT id,fieldNumber,fieldData FROM iso_fields) AS SourceTable
PIVOT
(
 SUM(fieldData) 
FOR fieldNumber IN ([4],[202],[203])
) AS PivotTable;
</code></pre>

<p>Error :</p>

<pre><code>Operand data type varchar is invalid for sum operator.
</code></pre>

<p>Reason: </p>

<pre><code>Table using varchar instead of int
</code></pre>

<p>What can i do about it? There is no way to alter the table back. </p>