Select all fields with some custom mappings

[cur53onu]

I have the pattern query and I want to select all fields with some of our custom mapping can we do this?
ex:
from every( e1=TempStream ) -> e2=TempStream[ e1.roomNo == 25 and (e1.temp + 5) <= temp ]
within 10 min select e1.roomNo, e1.temp as initialTemp, e2.temp as finalTemp
insert into AlertStream;
for this type of query I want to select all fields from e1 and e2 and I want to add some custom field (which are not there in e1 and e2) in AlertStream

[pranjal0811]

I want to run the query like this -
can it be possible ?

from every( e1=TempStream ) -> e2=TempStream[ e1.roomNo == 25 and (e1.temp + 5) <= temp ]
within 10 min select e1 as event1, e2 as event2 , 'custom' as customeString
insert into AlertStream;