[BUG] Column of NULL detects as VARCHAR

[joocer]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behaviour:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behaviour
A clear and concise description of what you expected to happen.

Screenshots or Logs
If applicable, add screenshots or logs to help explain your problem.
!! Be aware not to publish any sensitive information in what you upload.

Environment (please complete the following information):

• OS: [e.g. iOS]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.