ORDER BY RAND() sembra essere meno che casuale

RAND() viene eseguito solo una volta per query. Puoi verificarlo guardando il set di risultati.

Se stai cercando di ottenere un ordine casuale, dovresti utilizzare NEWID() o CHECKSUM(NEWID()) .

WITH T AS ( -- example using RAND()
  SELECT 'Me' Name UNION SELECT 'You' UNION SELECT 'Another'
)
SELECT Name, RAND()
FROM T;

WITH T AS ( -- example using just NEWID()
  SELECT 'Me' Name UNION SELECT 'You' UNION SELECT 'Another'
)
SELECT Name, NEWID()
FROM T;

WITH T AS ( -- example getting the CHECKSUM() of NEWID()
  SELECT 'Me' Name UNION SELECT 'You' UNION SELECT 'Another'
)
SELECT Name, CHECKSUM(NEWID())
FROM T;