Hi Lorenzo,
If each collection row needs to be exactly the same, i.e. Coll1.Row1.Value = Coll2.Row1.Value. You may find the action "Read Collection Field", as you can specify the field and row number. Use this against both collections, with the row number getting updated after each check. (You could do an initial row count to check the size of each collection).
Getting the value from each collection, you can compare them in a decision. Then once the row number exceeds the row count, you are finished.
If it doesn't matter what row the values are in, perhaps a filter (into a separate collection, to maintain the original) will better show if the value exists as required.
Let me know if you need either of those ideas better explained.
Thanks
Ben
Ben Lyons
Principal Product Specialist - Decipher
SS&C Blue Prism
UK based