how to convert Row to column dynamically in sql server - sql

Question

Here is my tables structure
Result
id ResultId CategoryId Total Attempted Score
----------------------------------------------------
1 8 1 30 25 20
2 8 2 30 30 19
3 8 3 30 27 21
4 7 1 20 15 10
5 7 2 20 20 15
Category
Id CategoryName
-----------------------
1 General
2 Aptitude
3 Technical
I want data in the below format
For ResultId = 8
Id General Aptitude Technical Total
--------------------------------------------------
8 20 19 21 60
For ResultId = 7
Id General Aptitude Total
-------------------------------------
7 10 15 25
I need a help to fetch the data in above format.
NOTE: The final fetched data contains score from Result table but having a column names from category table and according to CategoryId in Result table. Column name will be dynamic
Tried the below code (just for testing) but didn't work
DECLARE #SQLQuery AS NVARCHAR(MAX)
DECLARE #PivotColumns AS NVARCHAR(MAX)
SELECT #PivotColumns= COALESCE(#PivotColumns + ',','') + QUOTENAME(CategoryName)
FROM ( SELECT DISTINCT CategoryName
FROM [dbo].[Category] c) AS PivotExample
SET #SQLQuery =
N'SELECT DISTINCT ' + #PivotColumns + '
FROM [dbo].[Category] c
PIVOT( SUM(c.Id)
FOR CategoryName IN (' + #PivotColumns + ')) AS P'
EXEC sp_executesql #SQLQuery

Answer 1

My query will give you the expected output. You can check the output in SQL Fiddle
--dynamic with case
DECLARE #Sql NVARCHAR(4000) = NULL
DECLARE #ColumnHeaders NVARCHAR(4000);
SET #ColumnHeaders = STUFF((
SELECT DISTINCT ',' + 'Max(CASE WHEN rn =' + quotename(rn, '''') + ' THEN Score else null end ) as ' + CategoryName + CHAR(10) + CHAR(13)
FROM (
SELECT CategoryName, row_number() OVER (ORDER BY CategoryName) rn
FROM ( SELECT DISTINCT CategoryName FROM Category) t0
) t1
FOR XML PATH('')
,TYPE
).value('.', 'varchar(max)'), 1, 1, '');
--print #ColumnHeaders
SET #sql = N' ;with cte as (
select * , Row_number() Over(Partition by ResultId Order by ResultId ) rn from
Result)
Select ResultId, ' + #ColumnHeaders + ', SUM(Score) Total from cte Group by
ResultId ';
EXECUTE sp_executesql #sql