change the column name while selecting from dyanamic table - sql

Question

Hi I have attendence query which will generate the attendence report with using PIVOT function
Here's the procedure :
declare #in_date DATETIME
/*Select all the stagign entries related to promotion id and investment type id */
/* also only those staging daat related interface status tracking*/
-- Getting all distinct dates into a temporary table #Dates
SELECT a.date as full_date_of_attendence INTO #Dates
FROM dbo.getFullmonth(#in_date) a
ORDER BY a.date
-- The number of days will be dynamic. So building
-- a comma seperated value string from the dates in #Dates
SELECT #cols = COALESCE(#cols + ',[' + CONVERT(varchar, full_date_of_attendence, 106)
+ ']','[' + CONVERT(varchar, full_date_of_attendence, 106) + ']')
FROM #Dates
ORDER BY full_date_of_attendence
--select #cols
---- Building the query with dynamic dates
SET #qry =
'SELECT * FROM
(SELECT admission_id, attendence_status , date_of_attendence
FROM dbo.tblattendence)emp
PIVOT (MAX(attendence_status) FOR date_of_attendence IN (' + #cols + ')) AS stat'
-- Executing the query
EXEC(#qry)
-- Dropping temporary tables
DROP TABLE #Dates
here is the output of the above query::
admission_id 01 May 2013 02 May 2013 03 May 2013
2 NULL 1 0
3 NULL 1 1
4 NULL 0 0
5 NULL 0 1
Here I want to change the names of the columns as 01,02,03......
and I want the values 1 as 'P' and 0 as 'A'
can anyone would help me to achieve this ??

Answer 1

I would suggest the following changes to your code. If you want a list of the days (1, 2, 3, etc), then you can use the DAY function.
Typically when I get a list of columns dynamically, my preference is using STUFF and FOR XML PATH, I would alter that code to the following:
select #colsPiv = STUFF((SELECT ',' + QUOTENAME(cast(day(full_date_of_attendence) as varchar(2)))
from #Dates
GROUP BY full_date_of_attendence
ORDER BY full_date_of_attendence
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
Then if you want to replace the 0 with an A and a 1 with a P, you will want to create a query to get a list of columns to replace the values:
select #colsSel = STUFF((SELECT ', case when ' + QUOTENAME(cast(day(full_date_of_attendence) as varchar(2)))+'= 1 then ''P'' else ''A'' end as '+QUOTENAME(cast(day(full_date_of_attendence) as varchar(2)))
from #Dates
GROUP BY full_date_of_attendence
ORDER BY full_date_of_attendence
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
Basically, this is creating a select list similar to this:
select case when [1] = 1 then 'P' else 'A' end as [1], ...
Then your final query will be:
SET #qry =
'SELECT admission_id, '+#colsSel +'
FROM
(
SELECT admission_id,
attendence_status ,
day(date_of_attendence) date_of_attendence
FROM dbo.tblattendence
)emp
PIVOT
(
MAX(attendence_status)
FOR date_of_attendence IN (' + #colsPiv + ')
) AS stat'
See SQL Fiddle with Demo

Answer 2

Let's change just the two things you wanted to, i.e.
CONVERT(CHAR(2), full_date_of_attendence, 106) -- use CHAR(2) instead of varchar
CASE attendence_status when 1 then 'P' else 'A' END in the SELECT...
The code with minimal changes. Hope this helps you see how you can make similar changes in future to other code.
declare #in_date DATETIME
/*Select all the stagign entries related to promotion id and investment type id */
/* also only those staging daat related interface status tracking*/
-- Getting all distinct dates into a temporary table #Dates
SELECT a.date as full_date_of_attendence INTO #Dates
FROM dbo.getFullmonth(#in_date) a
ORDER BY a.date
-- The number of days will be dynamic. So building
-- a comma seperated value string from the dates in #Dates
SELECT #cols = COALESCE(#cols + ',', '') + [' +
CONVERT(CHAR(2), full_date_of_attendence, 106) + ']'
FROM #Dates
ORDER BY full_date_of_attendence
--select #cols
---- Building the query with dynamic dates
SET #qry =
'SELECT * FROM
(SELECT admission_id, CASE attendence_status when 1 then 'P' else 'A' END, date_of_attendence
FROM dbo.tblattendence)emp
PIVOT (MAX(attendence_status) FOR date_of_attendence IN (' + #cols + ')) AS stat'
-- Executing the query
EXEC(#qry)
-- Dropping temporary tables
DROP TABLE #Dates