How do I add a MySQL linked server to SQL Server?
We have a linked server on SQL pointing to a MySQL server.
Creating the linked server is a pretty straightforward thing.

The tricky part is getting the permissions sorted out on MySQL side.

If memory serves my right you need to create a local account on the SQL server and create an login on the MySQL server for the full computer name where the linked server will run.

On the SQL server I have a login for Sqltest. This is a SQL account

On the linked server properties I have "Security" > Be made using this security context > MySQL login username and password 

On the MySQL box I have a login for Sqltest@myserver.com. This is where my linked server failed for quite a long time.