Special identifiers in WHERE clause

[ArthurBesse]

I am trying to create a custom JDBC connector, and will appreciate any help for solving the following problem.

I have the following query:

SELECT FIELD1,FIELD2 FROM CATALOG_NAME.SCHEMA_NAME.TABLE_NAME WHERE SPECIAL_FIELD = 10;

SPECIAL_FIELD is not an existing column name in my table, it is some parameter that my JDBC driver expects.
So my JDBC driver can process the above mentioned query without any problem. But when I run that query with trino-cli I get an error about the non-existing column name.

For some reason I want to avoid modifying the query (for example ChatGPT suggests instead of using where clause to specify SPECIAL_FIELD as session property).
The perfect solution for me will be the one that will allow to run the above mentioned query without any modification. But I am also ok with some modifications, the only requirement I should not violate is that the value for SPECIAL_FIELD should be specified in query statement.

Code for my JDBC connector is almost the same as the jdbc-connector-example code in repository with minimal changes.

P.s. I'm new to trino, so I appreciate your patience and willingness to help.

[martint]

It’s not clear to me how much flexibility you have in changing the query structure, but you could do:

WITH SESSION SPECIAL_FIELD = …
SELECT …

If you want to keep it in the WHERE clause, you’ll need to make your connector present a virtual column to represent the special field and implement the filter pushdown APIs to make it understand the constraint on that field.

[ArthurBesse]

Thank you!