Error 1064

I try to run this sql and it just keeps giving me a pop up of error 1064 and I'm not sure why.

According to the MySQL documentation, there is no option, as far as I can see, to add "if not exists" after "add column" https://dev.mysql.com/doc/refman/8.4/en/alter-table.html

So do i need to do away with the "if not exists", which I did this just now and it sends me an error message of damage can't have a default value.

LONGTEXT columns do not have a default value. This too is in the documentation. https://dev.mysql.com/doc/refman/8.0/en/blob.html