EJB-QL count query????

[Johann Dobbins]

How do I preform a query that returns the number of rows that meet a condition?

I assume its something like:

   

Query query = entityManager.createQuery(SELECT COUNT( u ) FROM Users AS u WHERE u.id like ?1)

Integer count = query.getSingleResult()

 

but i realize this is very wrong. help please?

thanks

[Johann Dobbins]

Johann Dobbins wrote:How do I preform a query that returns the number of rows that meet a condition?

I assume its something like:

   

Query query = entityManager.createQuery(SELECT COUNT( u ) FROM Users AS u WHERE u.id like ?1)

Integer count = query.getSingleResult()

 

but i realize this is very wrong. help please?

thanks

to clarify, i don't want to simply do:

Query query = entityManager.createQuery(SELECT FROM Users AS u WHERE u.id like ?1)

Integer count = query.getSingleResult().size()

because the select query has a few join fetches and would be quite expensive if there are more than a certain number of records. so, i would like to first count the number of records and only populate a result set if the number is small enough.

thank you

[Johann Dobbins]

help please?

[Reza Rahman]

Johann,

Take a look at the JPQL 'NEW' operator. That would really be the only way to do this. Otherwise, you could look into native queries.

Hope it helps,
Reza