There is a way to do like a Math product() function like a kind of sum()

[rfgsdfghsdfghsd]

Here a sum formula

SUM(
  SELECT(
    Deliveries[DeliveryCharge],
    AND(
      ([DateDone] >= [_THISROW].[BeginDate]),
      ([DateDone] < [_THISROW].[EndDate])
    )
  )
)

 Same thing but with a Product() function like in Google appsheet

PRODUCT(
  SELECT(
    Deliveries[DeliveryCharge],
    AND(
      ([DateDone] >= [_THISROW].[BeginDate]),
      ([DateDone] < [_THISROW].[EndDate])
    )
  )
)

https://support.google.com/docs/answer/3093502?hl=en#null

I pretty not understanding why a simple function like doesn't exist!

[WillowMobileSys]

AppSheet is now a Google company.  But it wasn't always.  The original company approach was to implement only those features needed and/or requested by an App Creator.

Bottom line, no one has, up to now, seen a need for the PRODUCT() function.

Please feel free to add a Feature Idea to suggest that it be added.  You will want to be sure to include use cases so other can see the value of adding it into the platform.

[MultiTech]

Legit had to google PRODUCT()