Whether a function's output can be null: all but the counts and the rank
functions, though the engine types Sum and Average as never null (PLAN
§5.7, D4); a row function's is empty when there is no such row (PLAN §11.9). It decides rows: a negated filter guards with isEmpty only on a
nullable column.
Whether a function's output can be null: all but the counts and the rank functions, though the engine types Sum and Average as never null (PLAN §5.7, D4); a row function's is empty when there is no such row (PLAN §11.9). It decides rows: a negated filter guards with
isEmptyonly on a nullable column.