SELECT
        sn.instance_number         ,
        sga.allo sga               ,
        pga.allo pga               ,
        ( sga.allo + pga.allo ) tot,
        Trunc (SN.end_interval_time, 'mi') TIME
FROM
        (
                SELECT
                        snap_id        ,
                        instance_number,
                        Round (SUM (bytes) / 1024 / 1024 / 1024, 3) allo
                FROM
                        dba_hist_sgastat
                GROUP  BY
                        snap_id             ,
                        instance_number) sga,
        (
                SELECT
                        snap_id        ,
                        instance_number,
                        Round (SUM (value) / 1024 / 1024 / 1024, 3) allo
                FROM
                        dba_hist_pgastat
                WHERE
                        name = 'total PGA allocated'
                GROUP  BY
                        snap_id             ,
                        instance_number) pga,
        dba_hist_snapshot sn
WHERE
        sn.snap_id         = sga.snap_id
AND     sn.instance_number = sga.instance_number
AND     sn.snap_id         = pga.snap_id
AND     sn.instance_number = pga.instance_number
ORDER  BY
        sn.snap_id DESC,
        sn.instance_number;