Dynamic pivot query in sql server - sql

Question

I have a functioning pivot query for static column values which i want to convert for dynamic column values.
The query is :
with a as (
select request_id, dateadd(month,datediff(month,0,logged_datetime),0) as 'Month'
,dateadd(month,datediff(month,0,logged_datetime),0) as 'Year'
from requests
)
select * from (
select datepart(m,a.Month) as 'months',datepart(YEAR,a.Year) as 'years',a.request_id
from a ) ps
pivot (
count(request_id) for [years] in ([2008],[2009],[2010],[2011],[2012],[2013],[2014],[2015])
) as pvt
order by months
For the dynamic query written below I am getting errors like
Msg 207, Level 16, State 1, Line 5 Invalid column name '2010'. :
select distinct datepart(year,dateadd(month,datediff(month,0,logged_datetime),0)) as 'Yearz'
into #t
FROM requests
DECLARE #Dynamic AS NVARCHAR(MAX)
DECLARE #ColumnName AS NVARCHAR(MAX)
SELECT #ColumnName= ISNULL(#ColumnName + ',','')
+ QUOTENAME(Yearz)
FROM (SELECT * from #t) AS Yea
SET #Dynamic =
N'
select * from (
select datepart(m,dateadd(month,datediff(month,0,logged_datetime),0)) as months,' + #ColumnName + ',request_id
from requests ) ps
pivot (
count(request_id) for [Years] in (' + #ColumnName + ')
) as pvt
order by months
'
EXEC sp_executesql #Dynamic

Answer 1

SAMPLE TABLE
SELECT * INTO #REQUESTS
FROM
(
SELECT 1 request_id, '2012-06-01' logged_datetime
UNION ALL
SELECT 2 request_id, '2012-05-01'
UNION ALL
SELECT 11 request_id, '2012-06-01'
UNION ALL
SELECT 12 request_id, '2012-05-01'
UNION ALL
SELECT 3 request_id, '2012-07-01'
UNION ALL
SELECT 4 request_id, '2013-09-01'
UNION ALL
SELECT 5 request_id, '2013-10-01'
UNION ALL
SELECT 6 request_id, '2014-01-01'
UNION ALL
SELECT 7 request_id, '2014-02-01'
UNION ALL
SELECT 8 request_id, '2014-03-01'
UNION ALL
SELECT 9 request_id, '2014-05-01'
UNION ALL
SELECT 10 request_id, '2015-11-01'
)TAB
QUERY
Get the column for years and order it in numeric order
DECLARE #cols NVARCHAR (MAX)
SELECT #cols = COALESCE (#cols + ',[' + CAST([YEAR] AS VARCHAR(4)) + ']', '[' + CAST([YEAR] AS VARCHAR(4)) + ']')
FROM (SELECT DISTINCT YEAR(dateadd(month,datediff(month,0,logged_datetime),0)) [YEAR] FROM #REQUESTS) PV
ORDER BY CAST([YEAR] AS INT)
Now pivot the query
DECLARE #query NVARCHAR(MAX)
SET #query = 'SELECT * FROM
(
-- We will get the count for a year and number of request_id in that month here as CNT column
select DISTINCT datepart(m,a.Month) as ''months'',datepart(YEAR,a.Year) as ''years'',
COUNT(*) OVER(PARTITION BY datepart(YEAR,a.Year),datepart(m,a.Month)) CNT
from
(
select request_id, dateadd(month,datediff(month,0,logged_datetime),0) as ''Month''
,dateadd(month,datediff(month,0,logged_datetime),0) as ''Year''
from #requests
)a
) x
PIVOT
(
MIN(CNT)
FOR years IN (' + #cols + ')
) p
ORDER BY MONTHS;'
EXEC SP_EXECUTESQL #query
Click here to view the result

Answer 2

I think you need to wrap your dynamic column names using the QUOTENAME function:
See example here: