Proper way to add value to Column

Eg. User chose Important count, I need to increament the value of impCount by 1 into the sql server database.

Doing the below is throwing an error

        <cfquery name="qryUpd" datasource="#dsn#">
             update xxxx
                 set
                     <cfif isdefined("arguments.argtImpCount") and IsValid("Integer",arguments.argtImpCount)#">                      

                        impCount = impCount + 1

                    </cfif>

                  active=1