I want to increment a number field, but the issue I have with the function Mathematical and date-time expression calculator in that when the field has a number it increments correctly, but for the very first increment the Number field is empty, so the function requests that it be initialised and fails.
{11002} = null ? 1 : {11002} + 1
Just for fun, this is an alternative expression:
{11002} = null ? 1 : sum(toNumberList(%{11002} + ", 1", ","))
sum([{11002}]) + 1