Customer not showing up on customer list, but can be found on database

I'm hoping someone can help me out here.

So one of my clients (lets say client A) made an order, and paid via credit card. However, we encountered 2 problems with this:

1. Client A's Order number is the same as another customer's (client B's) Order number

2. I can't find client A on the customer list in the admin backend. However, using PHPMYADMIN she appears on the zen_customers and zen_orders tables in the database.

Can someone please let me know what's going on? Our Zen cart version is 1.3.8a, and our server has PHP version 5.2.13.

Thanks!

Update: it appears the hosting provider made a server migration. However, during the migration, the site was still live and accepting orders, now the old database has some data that the new database doesn't have, and vice versa :(.

Can anyone tell me how to merge these 2 database without losing their unique data?

That requires advanced knowledge of how databases work and how Zen Cart data is stored ... which isn't something that can easily be handled with a simple forum post.

But, since your posts appear to be discussing a single customer and a single order, I recommend simply impersonating the customer and placing the order in the new system on their behalf. As for payment, you could temporarily enable the Check/MoneyOrder module and use that for payment, and then manually update the order's status in the admin to Processing assuming you've already got payment for the order. You might also consider adding some text in the order-comments box to explain that this is an administrative re-entry of the customer's order due to a database migration change that was taking place when they placed their order. Be sure to "remove" the Check/MoneyOrder module when you're done if you don't normally offer it as a payment option.

Thanks for the response DrByte.

I think I've already fixed the issue. I copied over the missing data from the old database to the new database and modified the unique IDs accordingly. The tables I modified are address_book, customers, orders and orders_total. Have I missed anything or am I good to go?

Well, your customers will likely have login troubles, or you'll have troubles viewing those customers if you haven't also created customer_info table records for them.
And, your orders will have no products in them if you've not included the orders_products table data, similar with orders_products_attributes, orders_products_downloads, etc.
And, your order status info will be missing any customer comments as well as all order status updates if you didn't copy the orders_status_history table records.
And there's likely more that I'm missing there.

The database schema and relationships are documented here: http://www.zen-cart.com/wiki/index.php/Developers_-_Database_Schema
I strongly recommend a good study of that information if you're going to go about manually playing with raw data.

It would have been faster to key in a couple new customers and orders manually via the storefront.

Got it. Thanks for the link, much appreciated!