SQL Update to increment existing fields <p>I have an SQL table called 'Sales'</p> <p>I have the fields</p> <pre><code>ShopID int TotalSalesValue numeric(18.2) </code></pre> <p>Contents</p> <pre><code>ShopID | TotalSalesValue 1 | 10.34 2 | 100 </code></pre> <p>I have a stored procedure where I pass in the ShopID and addistion sales. What this does is check if the Shop ID exists in the table and if it does not, then it INSERTS into the table. If it goes exists I issue the UPDATE command. However, It update comment replaces the existing value, what I want to do it add onto the existing TotalSalesValue, a += if you may.</p> <p>Can anyone suggest a way to do this.</p> <p>Thanks in advance</p>