Salesforce Tips: Roll-up summary with formula fields

Can Roll-up summary field works with Formula field? The answer is Yes and No.

 

Yes if the Formula field is not referring to a field from foreign object. Let me give you an example:

 

Project (Parent object)

  • Project Name (Text 50)
  • Due Date (Date)
  • Total Cost (Roll-up Summary : Sum of all child Project Items Calculated Cost)

 

 

 

Project Item (Child Object)

  • Project Item Name (Text 50)
  • Item Quantity (Number 18, 0)
  • Item Price (Currency 16, 2)
  • Calculated Cost (Formula = Item Quantity * Item Price)

 

 

 

 

No, if the Formula field is referring to another field in a different object. Let me use the same example:

 

Project (Parent object) (Same as above)
Project Item (Child Object)

  • Project Item Name (Text 50)
  • Item Quantity (Number 18, 0)
  • Related Item (Lookup : Product)
  • Calculated Cost (Formula = Item Quantity * Product.Price)

 

Note that the Calculated Cost is now referring to a field called Price in the Product object. Because of this reason, the Roll-up Summary field (Total Cost) in the Project Object will not work anymore.