I'm having an issue when pulling data from the Data Warehouse. I am pulling two files, one with visits broken down by week, the other broken down by week and tracking code. In the second file, I am seeing more visits than in the first, even though I'm using the same date range.
It makes sense that the visit count is higher when you look break it down by tracking codes. A visit can easily have more than one tracking code. Example:
the user goes to google, searches for product A, find your paid advertisement and click through to your website, the tracking trigger campaign A in AA and registers 1 visit. The user is not interested in the product and goes back to the google search result page and searches again, not another paid ad shows up which has campaign B tracking code. If the user clicks through on this paid ad as well, then you will also have 1 visit registered to that campaign.
In your first data extract (without the campaign tracking code), you will just see 1 visit, because the user had 1 visit within the 30 minute window. When you break it down with campaign code, you will see more visits as there is 1 registered for each campaign code.
I am suspecting the dimension tracking code may be wrong. Double check for a similar named item, Tracking Code (evar1) or something like it depending on number of your tracking code. May just be its the incorrect version selected.