Hi Palash,
I just had the exact same problem. It seems like an issue with the ‘sqlalchemy’ package when it tries to create the table column because no lenght is specified.
I found a ‘temporary’ solution:
Locate the following file:
~/.local/lib/python3.6/site-packages/sqlalchemy/dialects/mysql/base.py (might not be the same exact path) and right after the line: visit_VARCHAR
add the following:
if type_.length is None:
type_.length = 1024 # change 1024 to whatever lenght value you need
Save the file and run rasa again. The table is created, and all varchar columns will have that exact size. I hope you can move on with this solution for the moment.
Byeee
(Don’t forget this is a kind of ‘hack’ so once your table is created, you can actually remove those two lines.)