How to migrate products display nodes with multiple product references?
I'm in a similar boat, but doing an import for a content type. If data is prepared with multi-value fields as in your second table, I can import the data using Feeds and the plugin 'Feeds Tamper'. So I'm also looking at repeatable and efficient ways to arrange data with multi-fields in CSV format. Saw a post about using Drupal 7 'Feeds Tamper PHP' to do create the multi-valued fields here, https://www.reddit.com/r/drupal/comments/2tumv9/drupal_7x_feeds_tamper_column_values_to_single/co2hesj. &lt;-- Untested, just a reference. HTH.