A Hql-Query leads to a DB2 Error (Error-Code -415). This happens with the following mapping:
In the sample testcase - that I added - there is an abstract superclass (AEntity) with two subclasses (BEntity, CEntity). BEntity has two numeric fields A and B. CEntity has two string fields B and C. When querying the HQL "from hibernate.testcase.inheritance.AEntity" this leads to the DB2-Error -415 (SQL0415N The data types of corresponding columns are not compatible in a fullselect that includes a set operator or in the multiple rows of a VALUES clause of an INSERT or fullselect.).
Here is the resulting SQL:
select aentity0_.Oid as Oid0_, aentity0_.A as A1_, aentity0_.B as B1_, aentity0_.B as B2_, aentity0_.C as C2_, aentity0_.clazz_ as clazz_ from ( select B, nullif('x','x') as C, Oid, A, 1 as clazz_ from springma.B union all select B, C, Oid, nullif(0,0) as A, 2 as clazz_ from springma.C ) aentity0_
In the union all both columns B are mapped into the same selection column. This is a type conflict.
Hibernate 3.2.6, DB2 9.5 LUW on Solaris