Fetch one value from random row where value is not x
At a glance, I'm not convinced that your original query is too far from wrong.

Unless, I'm greatly mistaken, the only time it should be unable to return a results is when the target slug happens to have the MAX(id) as its id, and when that row is the only valid row to consider. If the only id greater than or equal to the randomized id value you've calculated is the one eliminated by the other WHERE condition, there are no rows to return.

If that's the case, then something like this may work:

SELECT slug, id, rand.pk FROM games
JOIN
  (SELECT ROUND(MIN(id) + RAND() * (MAX(id) - MIN(id))) AS pk
   FROM games WHERE slug &lt;&gt; '20piaedfl6ah') AS rand
WHERE slug &lt;&gt; '20piaedfl6ah'
  AND id &gt;= rand.pk
LIMIT 1;


Here's a fork of @Vérace's DBFiddle with your original query and my modification of it. I made sure that the row to avoid has the highest ID

Here, we've ensured that neither end of our range matches our row to avoid. As long as that's true, then we should be OK with any value in our range. If the rand.pk matches the slug to avoid (or matches no rows at all - I assume there may be gaps in the ID sequence), then we know there's at least one row available that's OK - the one that matches our MAX(id)value (which cannot be either a gap row, or the row to avoid).

In numerous runs of the DBfiddle, I never saw the second query (which is the one protected against not finding a match) take longer than the first - however, I must note that the time to set-up the schema is included there.

And, of course, if there's only one row available, and its slug matches, you would still find no rows - however, I'd hold that in that case, finding no rows is the correct behavior.