This is one of the commonly asked interview question in Informatica. What will be the outpyt when we don't select any port for group by?
Aggregator Transformation in Informatica
When Integration service start processing data for aggregator transformation , it first divide input data into multiple group based on the group by port. It start performing aggregate calculations for each row under that group and in the end it will contains last row for that group along with aggregated values ( say sum , avg etc).
When you are not selecting group by option the Aggregator treats the whole data as a single group and in that case you will get the last record, Because if you select the group by in any column so it will return the last record for that particular column so in the same way you will get the Last record when you don't check on group by option in Any column.
I found a detailed article on "Aggregator transformation without selecting group by" topic here.
you can also check some other example of Aggregator Transformation in Informatica
