DB Engine functions


Is there documentation for the list of functions available in the db engine?

I am trying to group by a substring of a field in an evaluate expression (group: "substring(slot.wuc, 0, 2)"), and I get the error
"Can't group on a projection that isn't handled by the db engine: 'substring(slot.wuc, 0, 2)'"

At the very least, is there another db engine function that could handle this case?



Not a specific answer to your question, but an alternative solution would be to create a stored calc field with the expression you need (substring(slot.wuc, 0, 2)) and then use that field in your evaluate call.

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Unfortunately It’s not a simple answer. In general, substring is one that the db engine can handle. However, I believe there is a limitation that if the 1st argument involves an fkey field then the db engine can’t currently handle it. And there is a further limitation that group is only supported by the db so it won’t work if any of the projections can’t be handled by it. Thus the generic message.

We should definitely document this as best as we can including its current limitations. Beyond that, the long term goal is that “it just works”. For different scenarios when that actually is realized will vary.