DSXchange

If the argument specified is the secondary or other sorted key, then LastRowInGroup() returns TRUE if the value of the specified column is about to change, or if any of its higher level of key columns are about to change. For example, if the primary sorted column is Col1 and the secondary sorted column is Col2, then LastRowInGroup(Col2) returns true when either the value in Col2 is about to change, or the value in Col1 is about to change. Therefore it can return true when Col2 is not about to change, but Col1 is, because Col1 is a higher level sorted key than Col2.

The data must be sorted in the job, so that the Transformer stage can detect that it is sorted. If the data is sorted before being input to the job, you can include a dummy Sort stage and set the stage's Sort Key property to Don't Sort (previously sorted) for every column on which the data was previously sorted.