sql server single row multiple columns into one column - sql

Question

I have table like this
Reg_No Student_Name Subject1 Subject2 Subject3 Subject4 Total
----------- -------------------- ----------- ----------- ----------- ----------- -----------
101 Kevin 85 94 78 90 347
102 Andy 75 88 91 78 332
From this I need to create a temp table or table like this:
Reg_No Student_Name Subject Total
----------- -------------------- ----------- -----------
101 Kevin 85 347
94
78
90
102 Andy 75 332
88
91
78
Is there a way I can do this in SQL Server?

Answer 1

DDL:
DECLARE #temp TABLE
(
Reg_No INT
, Student_Name VARCHAR(20)
, Subject1 INT
, Subject2 INT
, Subject3 INT
, Subject4 INT
, Total INT
)
INSERT INTO #temp (Reg_No, Student_Name, Subject1, Subject2, Subject3, Subject4, Total)
VALUES
(101, 'Kevin', 85, 94, 78, 90, 347),
(102, 'Andy ', 75, 88, 91, 78, 332)
Query #1 - ROW_NUMBER:
SELECT Reg_No = CASE WHEN rn = 1 THEN t.Reg_No END
, Student_Name = CASE WHEN rn = 1 THEN t.Student_Name END
, t.[Subject]
, Total = CASE WHEN rn = 1 THEN t.Total END
FROM (
SELECT
Reg_No
, Student_Name
, [Subject]
, Total
, rn = ROW_NUMBER() OVER (PARTITION BY Reg_No ORDER BY 1/0)
FROM #temp
UNPIVOT
(
[Subject] FOR tt IN (Subject1, Subject2, Subject3, Subject4)
) unpvt
) t
Query #2 - OUTER APPLY:
SELECT t.*
FROM #temp
OUTER APPLY
(
VALUES
(Reg_No, Student_Name, Subject1, Total),
(NULL, NULL, Subject2, NULL),
(NULL, NULL, Subject3, NULL),
(NULL, NULL, Subject4, NULL)
) t(Reg_No, Student_Name, [Subject], Total)
Query Plan:
Query Cost:
Output:
Reg_No Student_Name Subject Total
----------- -------------------- ----------- -----------
101 Kevin 85 347
NULL NULL 94 NULL
NULL NULL 78 NULL
NULL NULL 90 NULL
102 Andy 75 332
NULL NULL 88 NULL
NULL NULL 91 NULL
NULL NULL 78 NULL
PS: In your case query with OUTER APPLY is faster than ROW_NUMBER solution.

Answer 2

The simplest approach would be to use a UNIONclause
select Reg_No, Student_Name, Subject1, Total from YourTable union all
select Reg_No, Student_Name, Subject2, Total from YourTable union all
select Reg_No, Student_Name, Subject3, Total from YourTable union all
select Reg_No, Student_Name, Subject3, Total from YourTable
UNION
Combines the results of two or more queries into a single result set
that includes all the rows that belong to all queries in the union.
The UNION operation is different from using joins that combine columns
from two tables.
The following are basic rules for combining the result sets of two
queries by using UNION:
•The number and the order of the columns must be the same in all
queries.
•The data types must be compatible.

Answer 3

Check this Fiddle
;WITH MyCTE AS
(
SELECT *
FROM (
SELECT Reg_No,
[Subject1],
[Subject2],
[Subject3],
[Subject4]
FROM Table1
)p
UNPIVOT
(
Result FOR SubjectName in ([Subject1], [Subject2], [Subject3], [Subject4])
)unpvt
)
SELECT T.Reg_No,
T.Student_Name,
M.SubjectName,
M.Result,
T.Total
FROM Table1 T
JOIN MyCTE M
ON T.Reg_No = M.Reg_No
If you do want NULL values in the rest, you may try the following:
This is the new Fiddle
And here is the code:
;WITH MyCTE AS
(
SELECT *
FROM (
SELECT Reg_No,
[Subject1],
[Subject2],
[Subject3],
[Subject4]
FROM Table1
)p
UNPIVOT
(
Result FOR SubjectName in ([Subject1], [Subject2], [Subject3], [Subject4])
)unpvt
),
MyNumberedCTE AS
(
SELECT *,
ROW_NUMBER() OVER(PARTITION BY Reg_No ORDER BY Reg_No,SubjectName) AS RowNum
FROM MyCTE
)
SELECT T.Reg_No,
T.Student_Name,
M.SubjectName,
M.Result,
T.Total
FROM MyCTE M
LEFT JOIN MyNumberedCTE N
ON N.Reg_No = M.Reg_No
AND N.SubjectName = M.SubjectName
AND N.RowNum=1
LEFT JOIN Table1 T
ON T.Reg_No = N.Reg_No

Answer 4

You should look after the PIVOT operator :
http://technet.microsoft.com/en-us/library/ms177410(v=sql.100).aspx

Answer 5

> DECLARE #cols AS NVARCHAR(MAX),#query AS NVARCHAR(MAX)
>
> select #cols = STUFF((SELECT ',' + QUOTENAME(designation)
> from MyTable
> group by designation
> order by designation
> FOR XML PATH(''), TYPE
> ).value('.', 'NVARCHAR(MAX)'),1,1,'')
>
> set #query = N'SELECT Row, ' + #cols + N' from
> (
> select ''SS'' Row, SS AS Value , designation from MyTable
> UNION ALL
> select ''AS'' Row, [AS] AS Value , designation from MyTable
> UNION ALL
> select ''Vac'' Row, Vac AS Value , designation from MyTable
> ) x
> pivot
> (
> max(Value) for designation in (' + #cols + N')
> ) p '
> exec sp_executesql #query;
For more details: Convert row into column when number of row is not fixed