When working with dynamic SQL error invalid identifier, how can I fix it?

Question

Oracle

All hello guys!
Can you help in solving the problem (I need to update certain data in the 'tablename' table, the data that is taken from general_table )

declare
  tablename varchar(255) := 'CoolTable';
BEGIN
  select functable (tablename) into tablename from dual;  --возвращает наличие таблицы 
  for rec in (select g.acode, g.clcode  from general_table g  where rownum = 1) loop
 if tablename is not null then
execute immediate 'update ' || tablename || ' set accli = ' || rec.acode || ', clcode= ' || rec.clcode || ''; --данные из таблы general_table обновляются в таблице tablename
end if;
end loop;
end;

ORA-00904: "8989123123": недопустимый идентификатор 
ORA-06512: на  line 16

Both in the 'tablename' table and in the general_table table, all fields of type Varchar2(100), what else could be the error?

Answer 1

The varchar literals must be quoted:

execute immediate 'update ' || tablename || ' set accli = ''' || rec.acode || ''', clcode= ''' || rec.clcode || '''';