Use SQL subquery as tablename

Question

I want to get all specific scores from users whose tablenames are stored in a list of users, something like this:

SELECT Score
from (SELECT tablenameOfUser FROM `Users`)
WHERE X='something'
  AND Y='somethingElse'
ORDER BY Score

I get the error:

1248 - Every derived table must have its own alias

Answer 1

The error message says it all. You need an alias on your derived table.

SELECT Score
from (SELECT tablenameOfUser FROM `Users`)
WHERE X='something'
  AND Y='somethingElse'
ORDER BY Score

Should be:

SELECT Score
from (SELECT tablenameOfUser FROM `Users`) yourAlias
WHERE X='something'
  AND Y='somethingElse'
ORDER BY Score

Your subquery only has the tablenameOfUser column, so Score, X, and Y, will not be available and your query will still fail.