The following restrictions apply to CLOB, BLOB, and UDT types involved in set operations.
You cannot use set operators with CLOB or BLOB types, except in the case of the UNION ALL set operator.
- Multiple UDTs involved in set operations must be identical types because Vantage does not perform implicit type conversion on UDTs involved in set operations.
A workaround for this restriction is to use CREATE CAST to define casts that cast between the UDTs and then explicitly invoke the CAST function within the set operation.
- UDTs involved in set operations must have ordering definitions.
Vantage generates ordering functionality for distinct UDTs where the source types are not LOBs. To create an ordering definition for structured UDTs or distinct UDTs where the source types are LOBs, or to replace system-generated ordering functionality, use CREATE ORDERING.
For more information on CREATE CAST and CREATE ORDERING, see
Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.