MRP Master Schedule Status

SELECT   NVL(SUM(NVL(NVL(dates.schedule_quantity,
                                   dates.repetitive_daily_rate), 0)), 0) C_sched
            FROM     bom_calendar_dates  cal,
                     mrp_schedule_dates  dates
            WHERE    cal.calendar_date           BETWEEN
                                                GREATEST(NVL(dates.schedule_workdate,
                                                             trunc(:C_period_start)),
                                                             trunc(:C_period_start))
                                                     AND
                                                   LEAST(NVL
                                                        (NVL(dates.rate_end_date,
                                                             dates.schedule_workdate),
                                                             trunc(:C_period_start)),
                                                             trunc(:C_period_end)
                                                             - 1)
            AND    ( dates.rate_end_date             IS NULL
                 OR  cal.seq_num                 IS NOT NULL)
            AND      cal.calendar_code                = :P_CAL_CODE
            AND      cal.exception_set_id             = :P_CAL_EXCEPTION_SET_ID
            AND      NVL(dates.rate_end_date(+),
                         dates.schedule_workdate(+)) >= :C_period_start
            AND      dates.schedule_workdate(+)       < :C_period_end
            AND      dates.supply_demand_type(+)      = DECODE(:P_SCHED_TYPE,
                                                               1, 1, 2)
            AND      dates.schedule_level(+)          = :P_SCHED_VERSION
            AND      dates.schedule_designator(+)     = :P_SCHED_NAME
            AND      dates.organization_id(+)         = :C_PLANNED_ORG
            AND      dates.inventory_item_id(+)       = :C_item_id_master