Hi,

I'm trying to get a single string by concatenating a text field. Of course, the version of Postgres I'm using doesn't have the string_agg function, so I have to use array_agg:



However, it throws an "Unable to locate appropriate constructor on class" error, presumably because I don't know the return type to use for array_agg, and I can't seem to find it in the documentation:



Any help would be great, thanks.

hey there,

ive got the same problem here...i cannot use array_agg, also tried to use custom functions, without any success.

did you solve this already? i would be very interested :)

thanks,
balazs

i think i misunderstood your problem, and the previous post was about a different one, which i could solve anyways.

but now i also tried to use array_agg and with a constructor with a param Object. and the new problem is now that Hibernate wants to fetch a long value (i applied the function on table.id) and obviously the value returned after applying array_agg is not a long but a {l1,l2, ..., ln} list.

so i would like to ask you how can you fetch this list without an exception being thrown because of the long-list conversion?

thanks,
balázs

I could make it work by changing the variable types in the constructor to Object and making a casting, like this_

public Hospital(Object hospitalId, Object hospitalName){

log.debug("Hospital Id: {}",hospitalId);
log.debug("HospitalName: {}",hospitalName);

this.hospitalId= hospitalId.toString();
this.hospitalName= hospitalName.toString();

}

But in the named query it´s all strings. I am migrating from EclipseLink to hibernate and everything was working fine with strings before :-(