In SSRS, trying to use Last(), to return last row from dataset

I have an expression outside my table, where i'm trying to read the last record in from m开发者_运维百科y dataset. Is Last() not a valid function or something? It's not erroring, just nothing is getting displayed.

=Last(Fields!IntialBalanceRolling.Value, "SupplierTransaction")

you can sort your data descending and use this:

=First(Fields!IntialBalanceRolling.Value, "SupplierTransaction")

Is it possible you last row has a null value for this column?