我正在编写一个窗口函数，该函数应该创建一个月窗口，并且仅在所述月窗口内的更新标志字段中获取具有最大值的记录。

我的窗口函数有问题，当它应该只显示最大值时，它仍在窗口中显示所有结果。

我在下面留下了我的代码。请帮忙。

SELECT 
  gb1.SKU_Id,gb1.Warehouse_Code,gb1.Period_Start,gb1.country,tm.c445_month,tm.report_date,gb1.update_flag,max(gb1.update_flag) over (partition by tm.yearmonth order by gb1.update_flag range between unbounded preceding and current row ) as update_window,SUM(gb1.TOTAL_NEW_SALES_FORECAST) AS dc_forecast
FROM BAS_E2E_OUTPUT_GLOBAL_FCST gb1
  inner join (
    SELECT
       gb2.SKU_Id,gb2.Warehouse_Code,gb2.Period_Start,gb2.country,gb2.update_flag,gb2.report_date,tm1.week_date,tm1.c445_month,tm1.yearmonth
   FROM BAS_E2E_OUTPUT_GLOBAL_FCST as gb2
     left join (
       select distinct(week_date) as week_date,c445_month,yearmonth 
       from "PROD"."INV_PROD"."BAS_445_MONTH_ALIGnmENT" 
       group by c445_month,week_date,yearmonth 
     ) as tm1 on gb2.report_date = tm1.week_date
   group by SKU_Id,Warehouse_Code,Period_Start,country,update_flag,report_date,tm1.yearmonth
  ) as tm 
     on gb1.report_date = tm.week_date
    and  gb1.SKU_ID = tm.sku_id
    and gb1.Warehouse_Code = tm.warehouse_code
    and gb1.Period_Start  = tm.period_start
    and gb1.country = tm.country
GROUP BY
    gb1.SKU_Id,tm.yearmonth,gb1.update_flag