PL SQL error

Question

自己写的一个PL SQL 但是有点问题：
declare
   v_id teacher.teacherid%type;
   v_job_title teacher.title%type;
   v_wage_origin teacher.wage%type;
   v_wage_new teacher.wage%type;
   Begin
     v_id := &teacherid;
     SELECT a.title into v_job_title FROM TEACHER A  where v_id = teacherid;
     Dbms_Output.put_line ('教授的原工资'||v_wage_origin);
     Dbms_Output.put_line ('高工和副教授的原工资'||v_wage_origin);
     case
       when v_job_title ='教授' then
         update teacher set wage = wage * 3 where teacher.title = '教授';
         select teacher.wage into v_wage_new from teacher where teacher.title = '教授' where v_id = teacherid;
          Dbms_Output.put_line('增长后的工资'|| v_wage_new );
          when v_job_title = '高工' OR v_job_title  = '副教授' then
            update teacher set wage = wage * 2 where teacher.title in ('副教授','高工');
            select teacher.wage into v_wage_new from teacher where teacher.title in ('副教授','高工');
            DBMS_OUTput.put_line('增长后的工资'||v_wage_new);
            end case;
     end;error message: ORA-06550 
               PLS-00103:Encountered the symbol"_" when expecting one of the following:看样子 是这句v_id := &teacherid; 没有通过编译呀！
麻烦各位大虾 不吝赐教，小弟不胜感激！

Answer 1

 select teacher.wage into v_wage_new from teacher where teacher.title = '教授' where v_id = teacherid;
怎么两个where 
select teacher.wage into v_wage_new from teacher where teacher.title = '教授' and v_id = teacherid;

Answer 2

  select teacher.wage into v_wage_new from teacher where teacher.title = '教授' where v_id = teacherid;
两个where

Answer 3

 select teacher.wage into v_wage_new from teacher where teacher.title = '教授' where v_id = teacherid; select teacher.wage into v_wage_new from teacher where teacher.title = '教授' and v_id = teacherid;

Answer 4

的确是两个where，把最后那个改成and再运行看看。