Cela devrait fonctionner :
SELECT id, name, bitMaskValue,
SUBSTRING(
CASE WHEN bitMaskValue & 1 = 1 THEN ',1' ELSE '' END
+ CASE WHEN bitMaskValue & 2 = 2 THEN ',2' ELSE '' END
+ CASE WHEN bitMaskValue & 4 = 4 THEN ',4' ELSE '' END
+ CASE WHEN bitMaskValue & 8 = 8 THEN ',8' ELSE '' END
, 2, 64) As [values]
FROM yourTable