Question

Using Open JPA 2.0, Database is DB2 9.7. For query like SELECT COUNT(1) FROM USER WHERE FNAME := fname, JPA is converting the query to SELECT COUNT(CAST(? AS BIGINT)) FROM TABLENAME.
How to avoid the CAST to BIGINT?

Code sample below:

query = entityManager.createNamedQuery("qry.checkuser");
query.setParameter("fname", fname); 
Long count = (Long)query.getSingleResult();

Answer 1

What worked for me is:

SELECT COUNT(USER_ID) FROM USER WHERE FNAME := fname

Basically we need to use a non nullable column like Primary key column and with this change the CAST can be avoided which consumes additional CPU, a minor gain.