This looks wrong, because it’s missing a parameter:
INNER JOIN <TABLE_TO_JOIN_IN> ON <COLUMN_OF_TABLE_TO_JOIN_IN> = <COLUM_WITH_IDENTICAL_IDENTIFIER_IN_SEARCHED_TABLE>
It should be somewhat like this:
INNER JOIN CorpoFatturaAcquisti ON IntestazioneFatturaAcquisti.ID = CorpoFatturaAcquisti.ID
Because i will leave the office soon and be back next year, i’d like to recommend trying Valentina Studio for building your querry. It has a Designer which can help you visually construct such querrys and you can use it even in the free version: Valentina Studio Free Version Database Management Software