August 20, 2007 at 8:21 pm
Hi,
Some background:
I have a school. School have classrooms. Classrooms are divided into various sections (Section A, Section B and so on) . Sections have subsections. Every student is allocated a rollnumber(unique) in that subsection/section. However student is also given a choice to specify his own roll(DesiredRoll) in that section. If more than one student choose the same desired roll no in that subsection/section, there is a [TrackingNo] field that then starts keeping a count.
I have two tables : Students and StuHistory. The structure of the Student table is as follows :
IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Student]') AND type in (N'U'))
BEGIN
CREATE TABLE [dbo].[Student](
[RID] [int] NOT NULL,
[Class] [int] NULL,
[Section] [char](1) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[SubSection] [int] NULL,
[RollNo] [int] NULL,
[DesiredRoll] [int] NULL,
[TrackingNo] [int] NULL,
[Original_rollno] [int] NULL,
[StudentStatus] [int] NULL
)
END
GO
For the first unique desired roll no in that subsection/section the tracking no is always 0.
[StudentStatus] represents the following : (-1 for deleted, 0 for edited, 1 for newly inserted).
After every fortnight, i have to run a batchquery that does the following:
1. all students marked with -1 are moved to a table called StuHistory which has the same structure as that of Student.
2. Now oncethe -1 status students are moved, there will be a gap in the roll no. I want to reallocate the rollnos now, where rollnos = desired roll no taking into consideration the trackingno
So if 4 students have chosen the desired roll no as 5 and their current roll no is scattered in a subsection lets say 7, 10, 14,16, then while rearranging they will be together(grouped by subsection/section) and will be allocated roll no's 5,6,7,8. The other students will be moved down based on their desired roll nos. Over here i have to also fill the gaps caused because of the students who were deleted.
How do i write query for this? I have been struggling.
Script :
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (1, 1, N'A', 1, 1, 1, 0, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (2, 1, N'A', 1, 2, 2, 0, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (3, 1, N'A', 1, 3, 1, 1,0,1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (4, 1, N'A', 12, 1, 1, 0,-1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (5, 1, N'A', 12, 2, 1, 1, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (6, 1, N'A', 12, 3, 2, 0, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (7, 1, N'B', 5, 1, 3, 0, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (8, 1, N'B', 5, 2, 3, 1, 0 ,1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (9, 1, N'B', 5, 3, 3, 2, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (10, 1, N'B', 5, 4, 2, 0, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (11, 1, N'B', 5, 5, 2, 1, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (12, 1, N'B', 10, 1, 1, 0, 0, 1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (13, 1, N'B', 10, 2, 1, 1, 0, 1 )
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (14, 1, N'B', 10, 3, 1, 2, 0, -1)
INSERT [dbo].[Student] ([RID], [Class], [Section], [SubSection], [RollNo], [DesiredRoll], [TrackingNo], [Original_rollno], [StudentStatus] )
VALUES (15, 1, N'B', 10, 4, 2, 0, 0, 1)
Thanks.
August 21, 2007 at 12:55 am
Asked and answered here
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=88129
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