entity-framework - Linq to Entities ネストされたサブクエリ

Question

私はlinqにかなり慣れていないので、次のSQLをlinqに変換する際に問題があります。

select 
    c3.COURSE, c3.DESCR
from 
    (select c.courseprefix, MAX(c.coursesuffix) [coursesuffix]
    from 
        (select distinct SUBSTRING(course,1,3)[courseprefix], RIGHT(course, LEN(course) - 3) [coursesuffix]
        from PsCourses where LEN(course) >= 3 ) c
    group by c.courseprefix 
    ) c2 inner join PsCourses c3 on (c2.courseprefix + c2.coursesuffix) = c3.COURSE
where
    c3.COURSE_STATUS = 'A'
order by
    c3.course