In my recent project I have to generate a report that requires joining tables from 2 different Oracle databases and one Sybase database and then filtering the results. I have no control over the databases, strictly read only access, can't create any temp tables or so.

I had something similar in my previous project and the way I solved was by dumping the Resultset in ArrayList and than looping and filtering. Was not really happy with the approach.

Just wondering, if there is a better way to do this. Is there any standard approach to this problem (seems pretty common in large industrial environments).

Any help, pointers on how to do it in JDBC-Resultset approach (preferably) or iBatis SQL Maps or Hibernate would be appreciated.