Why this statement work fine
SELECT *
FROM TABLE
where FIELDn IN ('x','FOL')

and with param
SELECT *
FROM DATI
where ABBREVIA IN (:param)
i'm not able to setting the correct value?

:param = 'x','FOL' no good
:param = 'x,FOL' no good
:param = ''x'',''FOL'' no good
and so on......

Thanks a lot.