title: Access calulation fails if any field is null
body: <p>I'm performing a select on a single table, and I need to total the value in a set of related field, I have this in the 'field' portion in the query builder.</p>
  
  <blockquote>
    <p>TotalValue :
    [FIELD1]+[FIELD2]+[FIELD3]+[FIELD4]+[FIELD5]+[FIELD6]+[FIELD7]</p>
  </blockquote>
  
  <p>When I go to the 'table view' for the query, I only get a calculation where all the fields specified have values? But if all the fields have a value it works perfectly.</p>
  
  <p>In an attempt to see if this was realy the case I inserted each of the fields into the query, and I get a table that has missing values.</p>
  
  <p>Obviously not what I was expecting!</p>
  
  <p>Am I missing something obvious? Is it related to 'null' values in the fields?</p>
  
  <p>please help, thanks in advance</p>
  
  <p>David</p>