Sum custom fields in the Opportunity from the Opportunity Items

[Falerci]

Hi there,

I have created a custom field in the Opportunity Items, that has to be imported in the Opportunity. This scope of this field was to carry the "Months of Subsciption" of the potential customer from the Product to the Opportunity.

Till today, this relationship was one-to-one and worked perfectly with this workflow. (Attached Photo)

Now each Opportunity can have more than one item, so the Opportunity "Months of Subscription" has to be the sum of the related items. Do you know how can I make this sum?

From the workflow, checking the Attributes, I only found the item List so I cannot interact with each Item List.

Thanks

[tarasm]

It can be done by a Hook (code required), https://docs.espocrm.com/development/hooks/