An expression to be evaluated in comparison with a second scalar_expression, including derived periods.
Comparison operators do not support BLOB or CLOB type expressions. You can explicitly cast BLOBs to BYTE or VARBYTE and cast CLOBs to CHARACTER or VARCHAR, and use the result with comparison operators.
An expression that results in a UDT data type can only be compared with another expression that results in the same UDT data type.