Because earlier versions of DB2 SQL do not have outer join operators, certain limitations apply to outer joins in Query and Reporting: Referential integrity is implemented in the DB2 database ...

The Oracle SQL ... and DB2. The SQL development environment helps the programmer perform basic functions on supported non-Oracle databases. Developers can browse and execute basic SELECT queries ...

Are the joins being passed to DB2? Can your DB2 system use parallel processing to access the data more quickly? DB2 has a Resource Limit Facility to limit the execution time of dynamic SQL statements.