Optimization of query

Hello,
I have written a query but I am not sure if it is efficient.
There are two tables, USERS and SCORE. USERS can be of three types, administrators, supervisors, trainers. Each trainer is assigned to a supervisor, which is stored in the users table.
Now the issue is: A supervisor can view his scores and the scores for trainers assigned to him.
The query I have written is :

Code:

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SELECT s.* FROM score as s, users as u WHERE s.trainerid=u.userid AND u.supervisor=50
UNION
SELECT * FROM score WHERE trainerid=50;

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Is there a better way of achieving the result?
I am using MySQL 5.0.
Thank you.

I don't know if it will be any faster (I suspect it might be), but I think this is at least easier to read:

Code:

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SELECT s.*
FROM score as s
LEFT JOIN users as u ON (s.trainerid=u.userid)
WHERE s.trainerid=50 OR u.supervisor=50;

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..note that using .* in the select list is slower than specifying the fields.

Thank you. That is definitely easier to read. I need all the fields from the score table.