如果连接列为Name，则类似于:

If the connecting column is Name then something like:

UPDATE MyTable
SET Comm = (SELECT Fees 
            FROM MyTable mt2
            WHERE mt2.Name = MyTable.Name
            AND mt2.Id != MyTable.Id)

但是，如果您有两个以上的同名行，则失败，因此应扩展这种情况下的条件.

However that fails if you have more than 2 rows with the same name so the condition in that case should be expanded.