update fee_schedule fs set fs.branch_id=
(
SELECT  branch_id  FROM   (SELECT  branch_id
                                       ,updated_ts
                                       ,gr_number
                                      ,row_number() OVER (PARTITION BY gr_number ORDER BY updated_ts desc) AS sno
                                FROM   admission_log ) x
                       WHERE  x.gr_number = fs.gr_number and to_char(x.updated_ts,'yyyymm') < fs.schedule_month
                       and rownum=1
                       order by sno
)
where fs.branch_id is null ;

sql错误：ora-00907:缺少右括号00907。00000-“右括号缺失”
我试着用的是同样的东西：

update fee_schedule fs set fs.branch_id=
(
select c.branch_id
      from (select b.branch_id,updated_ts,
                   row_number() over(PARTITION by b.gr_number order by b.updated_ts desc) as Sno
                   from admission_log b
                   where b.gr_number = fs.gr_number and to_char(b.updated_ts,'yyyymm') <  fs.schedule_month ) c
      where c.sno = 1
)
where fs.branch_id is null ;

我发现这个错误：
sql错误：ora-00904：“fs.”“schedule\u month”：标识符无效