Question

I am using SQL Server 2008 and I have 4 tables StudentAbsentees, Students, StudentSections and Sections

In the StudentAbsentees table I am storing the studentId that are absent (absentees only) on a particular day like,

    StudentId     Time     Date        
   -----------   ------   ------
       1         10:00    2012-04-13

and in the StudentSections I am storing the studentId in a particular section like

 StudentId    SectionId
   ----------   ------------
      1              1
      2              1
      3              1

and in the Students table I am storing student details, likewise in Sections table I have section details like name and capacity of that section.

I need to join these tables and display whether the student is present/absent on a particular day… the result should be

StudentId    Status
---------    ------
    1         Absent
    2         Present
    3         Present

I can get the absentees list from these tables, I dunno how to display whether they are present/absent….can anyone help me here

Answer 1

select * from (
   select s.id, 
          case 
              when sa.date = '2012-01-01'
              then 'absent'
              else 'present' 
          end as status,
          ROW_NUMBER() OVER (PARTITION BY s.id ORDER BY CASE WHEN sa.date = '2012-01-01' THEN 1 ELSE 2 END) AS RowNumber
   from students s
   left outer join studentabsentees sa on s.id = sa.studentid
)
as a where a.RowNumber = 1