ms访问中的语法错误（缺少运算符）

Question

我正在尝试使用以下查询，但是它表示缺少运算符和语法错误。 此问题与ms访问有关。

select s.student_id, e.average_second_year_marks, e.average_third_year_marks, e.overall_marks
from students s
join
(
  select student_id,
    avg(case when program_year_when_enrolled = 'Second' then marks_obtained end)
      as average_second_year_marks,
    avg(case when program_year_when_enrolled = 'Third' then marks_obtained end)
      as average_third_year_marks,
    (
     (sum(case when program_year_when_enrolled = 'Second' then marks_obtained end) * 1.0) +
     (sum(case when program_year_when_enrolled = 'Third' then marks_obtained end) * 2.0)
    ) / 3.0 as overall_marks
  from enrollment
  group by student_id
) e on e.student_id = s.student_id
where s.course_current_status = 'Graduated-2017'

Answer 1

等效的MS Access查询将更像这样：

select s.student_id, e.average_second_year_marks,
       e.average_third_year_marks, e.overall_marks
from students as s inner join
     (select student_id,
             avg(iif(program_year_when_enrolled = "Second", marks_obtained, NULL)) as average_second_year_marks,
             avg(iif(program_year_when_enrolled = "Third", marks_obtained, NULL)) as average_third_year_marks
             (1.0 * avg(iif(program_year_when_enrolled = "Second", marks_obtained, NULL)) +
              2.0 * avg(iif(program_year_when_enrolled = "Third", marks_obtained, NULL)) 
             ) / 3.0 as overall_marks
     from enrollment
     group by student_id
    ) as e 
    on e.student_id = s.student_id
where s.course_current_status = "Graduated-2017";