Subquery to calculate sum of same field multiple time of same Measurement


I was writing a subquery to calculate multiple sum with different condition for a field. But it is resulting only sum of first. Below is my query and please help me to solve this issue.

SELECT sum(“txn_41”), sum(“txn_42”) from (SELECT “txn_id” as “txn_41” from “measurement1” where “level”=‘41’), (SELECT “txn_id” as “txn_42” from “measurement1” where “level”=‘42’)

Any Ideas and explanations are welcome

//Best Regards
Joel T Stephen