如何将SUM(FAMOUNT_BASE)与SUM(FDISCRATE) 的差值,写进下面的语句 ?select SUM(FAMOUNT_BASE),SUM(FDISCRATE) FROM (SELECT MA.FCODE,MA.FAMOUNT_BASE,DE.FDISCRATEFROM BS_MV_SA_MA MA INNER JOIN BS_MV_SA_DE DEON MA.FMID=DE.FPIDWHERE TO_CHAR(MA.FBIZTIME,'YYYYMMDD')= TO_CHAR(sysdate,'YYYYMMDD')-1AND MA.FSTATE=6AND MA.FORG_STORE_CODE NOT LIKE 'S%'UNION ALLSELECT MA.FCODE,MA.FAMOUNT_BASE,DE.FDISCRATEFROM BS_MV_SA_MA MAINNER JOIN BS_MV_SA_DE DEON MA.FMID=DE.FPIDWHERE TO_CHAR(MA.FBIZTIME,'YYYYMMDD')= TO_CHAR(sysdate,'YYYYMMDD')-1AND MA.FSTATE=6AND MA.FORG_STORE_DE_CODE NOT LIKE 'S%' )