select e.emp_no,e.first_name,e.last_name,eb.btype,s.salary, case btype when 1 then round(salary*0.1,1) wnen 2 then round(salary*0.2,1) else round(salary*0.3,1) end as bonus from employees e join salaries s on e.emp_no=s.emp_no join emp_bonus eb on eb.emp_no=e.emp_no where to_date='9999-01-01' order by e.emp_no asc; 我在case里的then后面用round为什么总是报错啊？