We are developing software that generates and executes SQL queries for Oracle and SQL Server using ODBC drivers. We are researching the possibility to expand to DB2, but I read that there are several versions available. DB2 for LUW, for iSeries and for z/OS.
Are there any differences in SQL of SQL/PLSQL functionality in these versions?
As a ISV, is it possible to get a development environment for DB2 for iSeries or z/OS
As many other answers already say, there are differences between the members of the DB2 family. All DB2 are SQL-99 complaint, and each member has specific features of the following SQL standards (2003, 2006, 2008, 2011). Also, some extra features have been added to each member, for example autonomous transaction or modules in LUW.
There is a group in IBM called SQL Language Council (SLC) and its purpose is to discuss about the DB2 family compatibility. The following articles written by the SQL architects (Serge Rielau and Rick Swagerman) talk about that:
This group creates a document called SQL Reference for Cross-Platform Development that describe the compatibility between members of the family. The current version is 4.0, and it groups the features of the current DB2 versions.
Also, a recent series of articles in DeveloperWorks talk about the features in each member of the family. That gives you the portability between DB2:
More info: