Data export of not-triggered columns.

Hi,

In out project we have special rules regarding a "default email address" column in a table Person. We construct addresses with help of a special script that is called in a template of the column. But we suspect that not all active identities have triggered this template and therefore have "wrong" email addresses. So we would like to estimate numbers of such identities. Is there a way (SQL query e.g) to retrieve all Person whose default email addresses will change if we trigger the template?