Thank you Ryan for this detailed explanation!
Importing quotes from Magento 1.5 to 1.9
This assumes that you have two sites, 1) an old one and 2) a new one. Both of these sites should have Cart2Quote installed and your old site should have quotes populated.
1) In phpMyAdmin, navigate to your OLD database and export all Cart2Quote tables using following settings:
a) Go to ‘export’ from your database main view
b) select only the Cart2Quote tables to export
c) Scroll down and tick ‘Disable foreign key checks’
d) tick the radio button ‘data;
Data creation options
e) Scroll down and select ‘REPLACE’ for ‘Function to use when dumping data:’
f) Click ‘Go’ This will export your SQL file
2) In phpMyAdmin in your NEW database, import the SQL file that you just exported. If you go into Magento now and Navigate to a quote details page it should kick out the Magento error page. This is likely because of the fact that newer Cart2Quote database tables are different than older versions.
3) Make sure all values are ‘USD’ (or other currency) for ‘currency’ column in table ‘quoteadv_customer’
a) Go to the ‘SQL’ page from the top menu
b) Paste the following SQL statement into the text area and then click ‘Go’
SET currency = 'USD';
4) If your new Magento installation has different product IDs (SKUs can be the same though IDs are different, this will break the quote details page because it will be looking up the wrong value). You will need to painstakingly check new vs old IDs and fix these manually.
Go through and find the product ID in ‘quoteadv_request_item,’ checking against product ID in new/different Magento site
SET product_id = 'NEW #’
WHERE product_id = ‘OLD #’;
SET product_id = 'NEW #'
WHERE product_id = 'OLD #';