Hi @Herman_Tan, I am very sorry you are having trouble.
I was able to reproduce this on my side and shall add it to our engineering backlog for a closer look and fix.
In the meantime I was able to specify a different database by using a syntax like dw`.`test_table so n8n cam add the leading and trailing backticks without breaking the query:
Hope this is a suitable workaround for you until the problem is fixed!