如何在SQL Server 2005中找到兩列的總和？

Question

我使用下面的步驟檢索總presents和absents使用樞查詢....我想SUM的Presents[P]而Absents[A]然后calculate percentage

ALTER PROCEDURE [dbo]。[GetAttendence]（@ Course_Id varchar（30），@Semester varchar（10））

AS
   SELECT DISTINCT Enroll_Number, Course_Id, Semester, Isnull([P],0) 
                                           As Presents, Isnull([A],0) As Absents

    FROM (SELECT Enroll_Number, Course_Id, Semester, Flag from Attendence ) ps
    pivot(Count(Flag) for Flag in ([P],[A])) as pvt 

    WHERE Course_Id = @Course_Id and Semester = @Semester

這是要實施的Forula

總和=禮物+缺席

百分比=（（現在/總和）* 100）

Answer 1

嘗試這個：

select Enroll_Number,
       Course_Id,
       Semester,
       P as Presents,
       A as Absents,
       P+A as SumPA,
       1.0*P/(P+A)*100 as Percentage
from
  (
    select Enroll_Number, Course_Id, Semester, Flag
    from Attendence
    where Course_Id = @Course_Id and 
          Semester = @Semester
  ) ps
pivot
  (
    count(Flag) for Flag in ([P],[A])
  ) as pvt