select random value from each type
- by Joseph Mastey
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
