select 1 random row with complex filtering

Question

I\'ve 2 tables:

first table users:

+-------------------------+---------+------+-----+---------+-------+
| Field                   | Type             


        

Answer 1

Have you tried switching not exists to left join?

SELECT DISTINCT *
FROM   profiles t1
LEFT JOIN
       proposal t2
ON     t1.id = t2.to_id
WHERE  t1.first_name IS NOT NULL AND
       t2.to_id IS NULL
ORDER BY RAND()
LIMIT 0 , 1

This will return you all rows of profiles, and to those that are not matched by a row in proposal it will assign NULL values, on which you can filter.

The result should be the same, but the performance may be better.