I have 1 spreadsheet with two columns: sku and old_url, and another with sku and new_url.
I want to make a new sheet with sku, old_url and new_url.
Some of the SKUs aren't in both, these should be discarded.
Is this possible?
Well this could be done using ISBLANK(), OR(), and IF() functions:
=IF(OR(ISBLANK(C11),ISBLANK(E11)),0,J11)
Suppose sku_with_old is at C (and olds are at D), and sku_with_new is at E (and news are at F). This expression then is a way to get skus which are only in both... Similarly you can get olds and news in H and K columns.
Let me know if You'd like to make it this way - but can't.