My SQL host is zymic.com. I owned a forum there with 200 members, but tonight I ran into an issue and deleted my forum files + my database. I have a backup of both, but when I import my SQL database backup, I get this error:
The issue here is you are creating an index on a TEXT field. A TEXT type can contain up to 64k of characters. This is too large for an index. What you can do is create an index on a subset i.e. the first 20 characters by doing the following
However, you should look closely at the usefulness of having an index on only the first few characters. I suspect that you would be better off using full text searches which allows you to search for content within the text.
An index will use the contents of the column as a reference which links back to the actual row of data. However, I suspect that this is an index you actually don't ever use and you could also have removed it completely from your create table script.
If it was needed and you are issuing queries such as WHERE message LIKE 'abc%' then the index will use the first 20 characters of the message column to link back to the actual row.