CodePudding user response:

Group by didn't add an alias

CodePudding user response:

Group by how to add an alias? Added alias count (*)

CodePudding user response:

Ok, at the back of the group by field and select the back of the field, so add course. At the back of the group by course name

CodePudding user response:

Because both tables have this field, used to don't know which one do you want to use the
So you have to limit the table name or alias