Attach ratio for product versus accessory

[hpw]

I'm trying to set up a relation between products purchased and the amount of accessory for that product has been shold. To achieve this, I have the next tables. 

• Mapping table: Tells me to which sku which accessory (sp_refmodelno) belongs. A sku can have multiple accessories. 
• Product table: Maps all sold and purchase data. 
• Purchase orders: Information about the quantity bought per order/product
• Sales orders: Information about the quantity sold per order/product

For instance, I want a report that shows me that sku DXSP001 has been bought 181 times and a accessoiry (DXCF03) has been sold 72.557 times. I also like to know the attach ratio (72.557 / 181). 

What calculations do I need for this? 

[hpw · Accepted solution]

I found a solution by creating a relationship from the Mapping table directly to the Purchase Orders and Sales orders instead of having the Items table in between. 

[lbendlin]

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