title: Error converting data type varchar to numeric using cast
body: <p>I'm getting an error message when trying to do a SUM with a varchar field, I'm getting the following error even when using Cast?</p>
  
  <pre><code>Error converting data type varchar to numeric
  
  SUM(ISNULL(CAST(balance-current_balance_amount /100 AS float),0)) AS bal_diff
  </code></pre>