For User Defined Table Functions (UDTFs), a trick needs to be employed. Include a where clause whose only purpose is to push the UDTF invocation to the remote database!

3-part naming for UDTFs

--
-- Traditional 3-part name SQL would reference a table, view, or procedure
--
call otherRDB.schema.procedure123();
stop;

insert into localschema.fact_table
  select * from otherRDB.remoteschema.fact_table;
stop;

--
-- UDTF query that is run on a remote Db2 for i, and the results returned to the local IBM i
--
select current server, h.*
  from table (
      qsys2.history_log_info()
    ) h
  where exists 
    (select 1 from otherRDB.sysibm.sysdummy1);
stop;

I found this gist by accidentally discovering the same behaviour. Do you know if there's a way to force an IBM-supplied TF to run on the local database when a remote database is referenced elsewhere in the statment? I can find no obvious way of qualifying the TF call.

I'm trying to use QSYS2.OBJECT_STATISTICS for the local system, while referencing data from a remote system. LPAR.QSYS2.OBJECT_STATISTICS (or the slashed equivalent) generates a syntax error.

Hi,
There currently isn't a way to explicitly reference more than one database in a single query.
There are exceptions to the rule for some non-Query statements like INSERT with remote Subselect, and CREATE TABLE AS with remote subselect.
You could also have a UDTF that queries multiple IBM i's and then returns the results, making it appear that a single query can extract, compare, etc multiple IBM i's in a single query.
Regards, Scott

Thanks, I've used the CREATE TABLE AS caveat to effect my requirement. Hooray for QTEMP.