Salesforce Developer Community

Hi,

I have created a custom Tab called Iinvoices, where i would have multiple Invoices for a single Opportunity.

the Unique field that connects an Opportunity to an Invoice is "Purchase_Order_Number".

I am woundering if I can calculate the total of all the Invoices for a particular Purchase_Order_Number.

Please help

Thanks & regards,

Ganesh SN Lekshman