Related Lists expression

Hi, I have a list of related actions that were done at a client’s worksite. How do I write an expression that SUMs a column from that list of related actions?

Please use something like SUM(SELECT([Related actions][Column],TRUE)) with your own column names.

Here’s what I just came up with in the mean time.
SUM(Select(Action Record[Cost of Action],[Client ID]=[_Thisrow].[Client ID]))
Any suggestions? I think you’ve mentioned to me before about having it look through the related actions instead of the whole Action Record table?

The reason is simple… better to read it from the smaller virtual list than reading the whole child table again.

SELECT(..., TRUE)? TRUE? With SUM()?

TRUE belongs to SELECT()

Whoops! I misread! My bad!