如何从查询数据中获取相应的值

Question

我有以下的MSSQL表

Names
 sno     username    firstname
   1      jim         sam
   2      raj         ravi
   3      lion        king

Marks
 sno     from        given  
   1      raj         jim
   2      raj         lion
   3      lion        raj
   4      lion        jim   

现在我想显示我的表格，如下所示：

Select  [from],
        [given]
  From  Marks
  Where [from] = 'raj'

输出表：

from     given     firstname  
 raj      jim       sam
 raj      lion      king

我怎么能搞清楚呢？我无法理解它？

Answer 1

select marks.from, marks.given, names.fistname
  from marks
  join names
    on marks.given = names.username
 where marks.from = 'raj'