first.id and last.id

[ROHINISDAS]

please explain me the error formed?

[LinusH · Accepted solution]

Whenever you are using the BY statement the source data need to be sorted in the same way as specified in the BY statement.
Exception: when the data is stored in SPDE, SPDS or an external RDBMS the sorcerer engine sorts the data on the fly based on your BY statement.

[ROHINISDAS]

thank you for clearing my doubt.:-)