对两个数据库进行操作。。高手请帮忙！！！

Question

select g.stu_no,g.subject_name,gra= (case when r_no>50 then 50
                                             else r_no end) +
                                     (case when t_no>50 then 50
                                             else r_no end)
    from grade g inner join forum m on g.stu_no=m.stu_no

Answer 1

select g.stu_no,g.subject_name,gra= (case when r_no>50 then 50
                                             else r_no end) +
                                     (case when t_no>50 then 50
                                             else r_no end)
    from assingment..grade g inner join bbs..forum m on g.stu_no=m.stu_no