title: Update only one record in SQL Server conditionally
body: <p>I have the following result stored in a temp table <code>#tempResult</code> </p>
  
  <pre><code>SourceGuid           SourceTypeID         IsSelected
  -------------------- -------------------- ----------
  84588BAF068320450908      129                  0
  5367D0F80A0F4040E909      658                  0    &lt;
  872791440CDBE04F7C0B      658                  0    &lt;
  15ABA6B70E4A70463E0B      887                  0
  1DE39F9805A8A044B20B      887                  0
  3F96C93501144041D50A      887                  0
  6A01DFF705861049F509      887                  0
  </code></pre>
  
  <p>I need to make IsSelected value to 1 of <strong>only one and not both</strong> of the record marked with <code>&lt;</code> to 1 regardless of any other condition just SourceTypeID = 658</p>
  
  <p>How can I achieve this, thanks.</p>