HSQLDialect uses invalid select-clause null string for BLOB on HSQLDB 2.0 ------------------------------------------------------------------------- Key: HHH-5503 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5503 Project: Hibernate Core Issue Type: Bug Components: query-sql Affects Versions: 3.5.4, 3.5.5 Environment: HSQLDB 2.0 Reporter: Bart Bakker Assignee: Gail Badner The union select statement that is generated for multiple subclasses of an entity, when one of the subclasses uses a Lob, contains an invalid cast null on HSQLDB 2.0. From version 2.0 on HSQLDB supports data type BLOB and no longer forces using longvarbinary for blobs. While the HSQLDialect registers the appropriate column type for LOB now, it uses "cast(null as int)" in its getSelectClauseNullString in the union select described above, which causes HSQLDB error 'incompatible data types in combination'.