Item relation count based on customer behavior

[madhuqliklondon]

I am trying get number of customers who brought sample product and them later on dat brought standard product.
they have item relation id as it says they belong to same family but different product type.
consedering date of the order where standard product is purchased and checking back if they ever brought sample from same family which is based on item relation ID ID.
I have created monthyear field based on order dates so trying to get analysis month wise .
Thank you .
Below is the example.
Date	Customer	Order number	Item No_	Product Cat	Description
10/02/2017	1028245	24166068	6766	Sample	Boss The Scent For Her Eau De Sample
06/03/2018	1028245	30676250	6768	Standard	Boss The Scent For Her Eau de Parfum 30ml
Item relation id	Item No_	Product Cat	Description
1	6766	Sample	Boss The Scent For Her Eau De Sample
1	6768	Standard	Boss The Scent For Her Eau de Parfum 30ml