I have a mapping in a table (A) whichs searches for values (1 or 0) in another table (B). The relationship between the two tables is a one-to-many.
What I want to show in table A is the existence of a "1" in one of the related rows in table B. To do that I want to sum the results in table B and I though that would be able by using "sum" in combination with a mapping field in table A. So I wrote this:
However, on load the script returns an error: "invalid expression".
When I remvove the sum function but keep the rest of the mapping field intact, the script does not return an error (but is doesn't return the result I want either, of course).
Does anyone knows why I get an error when I try to apply the sum function to a mapping field?