Some time ago, I was asked to create an Access macro to recover all item pairs which share a common element. For example, imagine you want to link cited articles through citing articles, and you want to know which articles are the most cited together (a pair).

We set one table with 2 columns, the first one is the citing article ID, the second one is the cited article ID, and then the macro calculates all the possible pairs, with one loop inside another. With an example it's easier to understand:

Input Table