Hello
Using the latest Hibernate - quick question about HQL query using count:

I have two tables - Sessions and Messages. I run a from query on both of them although I mostly retrieve Session data.
The two tables have a foreign key relationship on sessionId - Messages have sessionIDs which tell them which sessions they contain (each msg contains 1 session). Sessions do not have message information.

I would like to do a simple count that tells me how many times a certain session occurs inside all the messages, while querying the entire Sessions table (using from Session).

Can anyone direct me to a solution? I cannot make this query work.

Best regards
Eyal

I'm basically trying to do the same thing and can't get it to work either. Also, I would like to save the count value as a property in my pojo, but it's not a mapped column, so I'm not sure how to do this.

There's an example using a Filter in the h3 docs under the Improving performance section. I use queries like the one below to test for the existence of objects. I think I got the original code from the 2.1.x docs.

I define a NamedQuery in my mapping file.

And the Java Code looks like this.

is it somehow possible to map the "count" value to a property in the pojo?

check out section 6.1.9 of the 3.0.5 docs. You can map a property to a formula which is an arbitrary SQL expression.

I haven't used this feature myself but it sounds like what you're looking for.

Thanks for the replies people.
However my query requires me to find this count for *each* item in my result list. Thus, I would like to initialize my count(*) function with a paramater that I receive in each item - the SessionID:



I understand that it is possible to do this type of count query with a single ID as input, but how can I use the sessionID I receive on the select clause from SessionObj to run the count query?

10x
Eyal