create or replace procedure IC_GETSEQUENCENUM(SEQUENCENAME in varchar2,--(100), --这里只需要定义变量类型，不需要定义大小
                                              SEQNUM       out number) as
begin
  select SEQUENCENAME.nextval into SEQNUM from dual; 
end IC_GETSEQUENCENUM

------解决方案--------------------
1,一楼说了定义变量类型，不要加()大小
2,sequence需要定义，不是拿来就可以nextval的

------解决方案--------------------
探讨

储存过程如下
create or replace procedure IC_GETSEQUENCENUM
(
 SEQUENCENAME in varchar2(100),
 SEQNUM out number
)
as 
begin
      select SEQUENCENAME.nextval into SEQNUM from dual; 
          
end……