I do the next SOQL and works:
SELECT FieldString FROM Account GROUP BY FieldString HAVING COUNT(FieldString)>1

But when I do the next SOQL doesn´t work:
SELECT FieldDouble FROM Account GROUP BY FieldDouble HAVING COUNT(FieldDouble)>1

Is it possible to make a format change for the SOQL to work? Or is there an alternative to making this SOQL work?
Thanks