I'm currently using IBM Data Studio 4.1 to run queries against DB2 LUW database(s). My understanding is that I can do cross database queries by prefixing the database(s) names.

For example, database.schema.table.

However, when I open a SQL Query window, there is a dropdown that requires the user to select the database connection. Since it only allows one database connection, how do we run cross database queries in IBM Data Studio?

2 Answers 2


For you to execute any SQL statement you have to be connected to some database server; Data Studio does not execute SQL statements. Subsequently, for the three part name (<server>.<schema>.<object>) to work the server you're connected to has to know what the <server> part is.

In the simple case of accessing objects in a database that belongs to the same Db2 for LUW database instance, <server> is the other database name, and no additional setup is required.

However, if the other table is in a database managed by a different instance, or if it belongs to a different DBMS (Db2 for z/OS, Oracle, etc.), you will need to set up a federated data source, whose name you will then use for <server>.

  • My understanding from your answer is that we first need to connect to a DB2 database instance. If that instance manages multiple databases, say DB_X and DB_Y then we could write a query that joins DB_X.Schema.Table to DB_Y.Schema.Table. Is my understanding correct? Thanks.
    – user137481
    May 13, 2021 at 3:17
  • You don't connect to an instance; you connect to a database (managed by an instance).
    – mustaccio
    May 13, 2021 at 13:21

I'm not familiar with DataStudio - their are other tools in the market like https://dbeaver.com/databases/ or https://www.dbvis.com. Their is a workaround for the last mentioned tool https://support.dbvis.com/support/solutions/articles/1000196586-can-i-access-tables-across-multiple-databases-within-one-statement PS I agree with - mustaccio - the best way is the setup federation - depending on license issue's https://www.ibm.com/docs/en/db2/11.1?topic=editions-functionality-in-db2-product-db2-offerings

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