-8006: Data types must be compatible 

Explanation:

...

       1.      A function was applied to a non-permitted argument.

       2.      A two-digit operation was applied to non-comparable values.

       3.      A predicate contains non-comparable data types.

Each data type can be compared to itself. Columns of data type CHAR with the different code attributes ASCII and UNICODE can be compared to each other; they are implicitly adapted. The columns of code attribute ASCII can be compared to date, time, and timestamp specifications.

All numbers can be compared to each other.

User Action:

Use a QUERY statement issued on the system table DOMAIN.COLUMNS to find out the definition of the specified columns. It may be attempted to achieve comparability by applying a conversion function.