Incorrect result when having null in case clause

[YuanchengJiang]

To reproduce

select case when null is null then null else null end

Result:

psycopg2.DatabaseError: not implemented for type 'unknown'
LINE 2: select case when null is null then null else null end

Expected Result:

null

Workaround:

select case when null is null then null else null::string end

QuestDB version:

7.4

OS, in case of Docker specify Docker and the Host OS:

ubuntu 22

File System, in case of Docker specify Host File System:

ext4

Full Name:

Yuancheng Jiang

Affiliation:

National University of Singapore

Have you followed Linux, MacOs kernel configuration steps to increase Maximum open files and Maximum virtual memory areas limit?

• Yes, I have

Additional context

No response