Merge two stores into one new one

We currently have two stores one for retail and one for wholesale. We set this up due to the some needs a few years back. But we are wanting to merge the two and upgrade to 1.3.9 from 1.3.7.1.

I have set up a fresh install and working on it and putting in the modules we want included dual pricing and a number of new module plus some of the module that we are currently using in the current stores. *Note not all of the current modules are being installed as we have not used them etc.

Now here comes my questions. I want upgrade the retail store and preserve all this data plus I want merge the customer and order details of the wholesale store. The problem is that the wholesale store didn't have all of the products that the retail store had.

But we want to preserve the customers from both databases and the orders associated with all customers. We have almost 5000 orders in the retail stores and only 400 in the wholesale store.

So what is the best way to upgrade the databases and to merge the customer and order data from wholesale to the new database as well as the retail data. We want to use Sales report and have this data accurate once everything is combined!

Thanks in Advance.

But we want to preserve the customers from both databases and the orders associated with all customers. We have almost 5000 orders in the retail stores and only 400 in the wholesale store.
You will have a real time at doing this as each customer gets an ID and a incremented # as created and there will be duplicates in your other shop
Orders area also ID'd and cross indexed to order history and on and on

... To add to what kobra is saying, you'll need to have someone with strong database skills renumber everything in your database before you can merge any records into one database.
Also, in so doing your wholesale customers' order numbers will all get changed to the new numbers you assign. They will not be informed of the new numbers unless you do so yourself. They can certainly review their orders by logging in to their accounts and then viewing their order history, which will of course then show them the new numbers.

If you don't have staff who possess strong database skills, especially specific to Zen Cart, then I suggest you post in the Commercial Help Wanted section to have people quote you on the work to be done.

Thanks for the feedback. I am pretty good with database work, but I might do as you suggest and get some help. I am hosted on Camelot hosting and I know they do offer help for zencart work for a fee. And they are great guys too!

I just wanted to get a perspective from the zencart community and at least now I know what needs to be done.

Thanks