Teiid designer: 8.3.3-Final. JDV: 6.0.0. Both aren't community versions but hopefully can still post questions here. As for the Jira issue: this appears to be an issue with null values in columns with type varbinary. In my case, there are no null values in the columns so perhaps this is something else?

Not very easily done in this situation (at the customer site in an isolated environment) but may be able to reproduce on a local installation. I am happy to do things manually if I know how I am able to convert from varbinary to string. I have tried some intermediate examples like first making the source model column be of type BLOB and then trying to explicitly convert that to String.

Some feedback from my side: teiid 8.7 is able to convert this properly. I do have to set the imported datasources back to varbinary, however, as it defaults to the Object type. This doesn't help me much, though, as we are not going to use a community version of JDV.

You can manually set the type of these fields to be varbinary and you may also have to manually set the fields to be SEARCHABLE in Teiid and then a JOIN does work. To what fields can I convert this to get a string or integer representation of these kinds of fields? Databases like SQL Server, for instance, are able to convert these kinds of fields to a string representation or to a BIGINT value but if I try to use the CONVERT function in Teiid/JDV to cast the field to a String or Bigint then I get an exception indicating that a conversion to that type is not possible. According to Type Conversions - Teiid 8.4 - Project Documentation Editor, it seems to be possible to first convert it to Object and then to another type but that seems rather cumbersome...