I have two tables, rating:

+-----------+-----------+-------------+----------+
| rating_id | entity_id | rating_code | position |
+-----------+-----------+-------------+----------+
|         1 |         1 | Quality     |        0 |
|         2 |         1 | Value       |        0 |
|         3 |         1 | Price       |        0 |
+-----------+-----------+-------------+----------+

And rating_option

+-----------+-----------+------+-------+----------+
| option_id | rating_id | code | value | position |
+-----------+-----------+------+-------+----------+
|         1 |         1 | 1    |     1 |        1 |
|         2 |         1 | 2    |     2 |        2 |
|         3 |         1 | 3    |     3 |        3 |
|         4 |         1 | 4    |     4 |        4 |
|         5 |         1 | 5    |     5 |        5 |
|         6 |         2 | 1    |     1 |        1 |
|         7 |         2 | 2    |     2 |        2 |
|         8 |         2 | 3    |     3 |        3 |
|         9 |         2 | 4    |     4 |        4 |
|        10 |         2 | 5    |     5 |        5 |
|        11 |         3 | 1    |     1 |        1 |
|        12 |         3 | 2    |     2 |        2 |
|        13 |         3 | 3    |     3 |        3 |
|        14 |         3 | 4    |     4 |        4 |
|        15 |         3 | 5    |     5 |        5 |
+-----------+-----------+------+-------+----------+

I need a SQL query (not application level, must stay in the database) which will select a set of ratings randomly. A sample result would look like this, but would pick a random value for each rating_id on subsequent calls:

+-----------+-----------+------+-------+----------+
| option_id | rating_id | code | value | position |
+-----------+-----------+------+-------+----------+
|         1 |         1 | 1    |     1 |        1 |
|         8 |         2 | 3    |     3 |        3 |
|        15 |         3 | 5    |     5 |        5 |
+-----------+-----------+------+-------+----------+

I'm totally stuck on the random part, and grouping by rating_id has been a crap shoot so far. Any MySQL ninjas want to take a stab?

Thanks, Joe