If you do not select any group by port in an Aggregator transformation and also want the first record of any input record set, then, simply use the FIRST function with no group by ports selected. Because, if there is no group by ports selected, by default, FIRST treats all rows as one group, returning one value. However, make sure that the first record is not NULL. If a value is NULL, FIRST
ignores the row.
--Or--
Dont use group by.By default it will give last row.To override it,use FIRST function.