ORA-32614: illegal MODEL SELECT expression

[qq_40608182]

执行以下SQL语句时，出现ORA-32614: illegal MODEL SELECT expression 错误提示。
请教下大神，什么原因造成的，如果解决？不甚感激！

select to_date(stat_date,'yyyy-mm-dd') as "时间",cust_num,new_cust_num,'口袋APP下载' as "指标类型",cn "指标项",cv "指标值"
  from (select stat_date,
               sum(cust_num) as cust_num,
               sum(cust_num)- nvl(lag(sum(cust_num))over(order by stat_date),0) new_cust_num,
               round(sum(app_num)*100/sum(cust_num),2) as app_rate,
               sum(app_num) as app_num,
               sum(app_num) - nvl(lag(sum(app_num))over(order by stat_date),0) new_cust_num2
          from tmp
         group by stat_date
       )
where stat_date is not null
model
return updated rows
partition by (stat_date)
dimension by (0 as n)
measures(cast('x' as varchar2(40)) as cn, cast(1 as number(30)) as cv, app_rate as c1,app_num as c2,new_cust_num2 as c3)
rules upsert all
(
cn[1] = 'App下载率(%)',
cn[2] = '累计下载客户数',
cn[3] = '当周新增客户数',
cv[1] = c1[0],
cv[2] = c2[0],
cv[3] = c3[0]
)

网上百度了下：
Description：illegal MODEL SELECT expression
Cause： An expression other than MODEL aliases, constants, or expressions of the two is specified in the MODEL SELECT clause.
Action： Reformulate the query, perhaps nesting inside another SELECT.

没看懂，求大神帮忙解答！

[qq_40608182]

引用 1 楼 qq646748739 的回复:

partition by (stat_date) 改成: partition by (stat_date,cust_num,new_cust_num) 试试看～

改了之后运行OK！

[qq_40608182]

可以帮忙再解释下以下英文吗？ 谢谢！ Description：illegal MODEL SELECT expression Cause： An expression other than MODEL aliases, constants, or expressions of the two is specified in the MODEL SELECT clause. Action： Reformulate the query, perhaps nesting inside another SELECT.

[碧水幽幽泉]

partition by (stat_date) 改成: partition by (stat_date,cust_num,new_cust_num) 试试看～