Database level import of featured images – How?

Hi,

I have been attempting to import about 50,000 images into 50,000 posts in WP 4.2.2. The _posts table data is all correctly imported already.

I know I need to import to _postmeta table and add new records to _posts too but I’m having big issues getting this right. I have the correct data to import in the format below so that Posts can be linked to PostMeta images via the ID column – how can I write some SQL or has anyone written any SQL to achieve this? The other option might be a free plugin but I can’t find the right thing to do the job – any help would be much appreciated!

ID image_name

46 victor_matfield5.jpg
65 victor_matfield6.jpg
74 victor_matfield7.jpg
160 victor_matfield5.jpg

Thanks!