Getting PIVOT using GroupBy - sql

Question

I have this table:
Person Job Day EndDay
1 101 1 12
1 102 2 11
1 103 3 11
3 101 1 11
3 102 2 11
3 JobOff 3 11
2 101 1 11
2 102 2 11
2 103 3 11
2 JobOff 4 11
...
PS: My days are upto 'N', which I don't know. So, static SQL is not feasible here.
And I need to change it to this form:
Day (Columns)
Person (Rows)
Person 1 2 3 4
1 101 102 103 N/A
2 101 102 103 JobOff
3 101 102 JobOff N/A
Any help would be appreciated. I am very new in SQL.
Thanks to Roman, I have this S.Procedure:
CREATE PROCEDURE [dbo].[MyStoredProcedure] AS
BEGIN
declare #stmt nvarchar(max)
select #stmt =
isnull(#stmt + ', ', '') +
'isnull(max(case when [Day] = ' + cast([Day_I] as nvarchar(max)) +
' then Job end), ''N/A'') as [' + cast([Day_I] as nvarchar(max)) + ']'
from (select distinct [Day_I] from dbo.Solution) as t
order by [Day_I]
select #stmt = '
select
Person_I, ' + #stmt +'
from dbo.Solution_Format
group by Person_I'
END
But when I am executing this stored procedure like this:
exec MyStoredProcedure
Its showing me NO results. No errors!

Answer 1

select
Person,
isnull(max(case when [Day] = 1 then Job end), 'N/A') as [1],
isnull(max(case when [Day] = 2 then Job end), 'N/A') as [2],
isnull(max(case when [Day] = 3 then Job end), 'N/A') as [3],
isnull(max(case when [Day] = 4 then Job end), 'N/A') as [4]
from Table1
group by Person
sql fiddle demo
it's also possible to do this with dynamic SQL if you need this to arbitrary number of columns:
create procedure [dbo].[MyStoredProcedure]
as
begin
declare #stmt nvarchar(max)
select #stmt =
isnull(#stmt + ', ', '') +
'isnull(max(case when [Day] = ' + cast([Day] as nvarchar(max)) +
' then Job end), ''N/A'') as [' + cast([Day] as nvarchar(max)) + ']'
from (select distinct [Day] from Table1) as t
order by [Day]
select #stmt = '
select
Person, ' + #stmt +'
from Table1
group by Person'
exec sp_executesql
#stmt = #stmt
end
sql fiddle demo

Answer 2

One way to do this is to use multiple self joins
Select
t1.Person,
COALESCE(t1.Job, 'N/A') [1],
COALESCE(t2.Job, 'N/A' )[2],
COALESCE(t3.Job, 'N/A') [3],
COALESCE(t4.Job, 'N/A') [4]
FROM
table1 t1
LEFT JOIN table1 t2
ON t1.Person = t2.Person
and t2.Day = 2
LEFT JOIN table1 t3
ON t1.Person = t3.Person
and t3.Day = 3
LEFT JOIN table1 t4
ON t1.Person = t4.Person
and t4.Day = 4
WHERE
t1.Day = 1
ORDER BY
t1.Person
DEMO
Another ways is to use MAX(CASE however I'm not a fan of using aggregates like this.
Select
t1.Person,
COALESCE(MAX(CASE WHEN t1.Day = 1 then t1.Job END), 'N/A') [1],
COALESCE(MAX(CASE WHEN t1.Day = 2 then t1.Job END), 'N/A') [2],
COALESCE(MAX(CASE WHEN t1.Day = 3 then t1.Job END), 'N/A') [3],
COALESCE(MAX(CASE WHEN t1.Day = 4 then t1.Job END), 'N/A') [4]
FROM
table1 t1
GROUP BY
t1.Person
DEMO
And lastly there's the pivot clause which I don't really like because of the MAX here
SELECT person,
COALESCE([1], 'N/A') [1],
COALESCE([2], 'N/A') [2],
COALESCE([3], 'N/A') [3],
COALESCE([4], 'N/A') [4]
FROM (SELECT t1.person,
t1.day,
t1.job
FROM table1 t1) p
PIVOT (Max (job)
FOR day IN ( [1],
[2],
[3],
[4]) ) AS pvt
DEMO