> org.postgresql.util.PSQLException: ERROR: operator does not exist: character varying = bytea
This has been discussed on Stack Overflow[0].
The answer with the highest approval suggests to use coalesce[1]:
```
Select * from A where middle_name = coalesce(?1)
```
Lutz
[0] https://stackoverflow.com/a/54223586
[1] https://www.postgresql.org/docs/current/functions-conditional.html#FUNCTIONS-COALESCE-NVL-IFNULL