custom query

custom query - how can we fetch the set of records based on BDM type attribute in custom query ?

i have two business objects as follows

employee - name String
- eType employeeType

employeeType - name String.

custom query :- SELECT e
FROM employee e
WHERE e.eType.persistenceId = :id
ORDER BY e.persistenceId ASC

the above query is not returning any result, i am using version 7.5.2