put same ID different rows in one line - sql-server

Question

How could I put those multiple rows into one line, and the contents are in different columns:
From:
ID | Subject1/Catalog/Session
10868952 | NUR/3110/D507
10868952 | NUR/3110/D512
10868952 | NUR/4010/D523
10868952 | NUR/4010/HD20
To
ID |Subject1/Catalog/Session |Subject2/Catalog/Session | Subject3/Catalog/Session |Subject4/Catalog/Session | Subject5/Catalog/Session
10868952 |NUR/3110/D507 | NUR/3110/D512 | NUR/4010/D523 | NUR/4010/HD20 |

Answer 1

Would be best if in the future you can provide ddl and sample data. I did this for you this time.
Here is how you could do this if you know the number of elements per row. I put links in the comments of the original post to both the static and dynamic versions of this type of approach.
if OBJECT_ID('tempdb..#Something') is not null
drop table #Something
create table #Something
(
ID int,
Subject1 varchar(50)
)
insert #Something
select 10868952, 'NUR/3110/D507' union all
select 10868952, 'NUR/3110/D512' union all
select 10868952, 'NUR/4010/D523' union all
select 10868952, 'NUR/4010/HD20';
with OrderedResults as
(
select *, ROW_NUMBER() over(partition by ID order by Subject1) as RowNum
from #Something
)
select ID
, MAX(Case when RowNum = 1 then Subject1 end) as Subject1
, MAX(Case when RowNum = 2 then Subject1 end) as Subject2
, MAX(Case when RowNum = 3 then Subject1 end) as Subject3
, MAX(Case when RowNum = 4 then Subject1 end) as Subject4
from OrderedResults
group by ID

Answer 2

Here is how you can do this as a dynamic pivot. There are a number of concepts going on here. One is a tally table. In this code it is implemented as a cte. In my actual system I have this as a view. It generates 10,000 rows with zero reads. The tally table and most of the other concepts here were learned by the immortal Jeff Moden. If you do not know what a tally table is or how they work, check out Jeff's article here. http://www.sqlservercentral.com/articles/T-SQL/62867/
I will post some code for how to do this for this example but anybody who is unfamiliar with this technique should read his article. http://www.sqlservercentral.com/articles/Crosstab/65048/
Here is a full working example of doing this as a dynamic cross tab. When you are satisfied that the sql this generates is safe feel free to uncomment the last two lines.
LAST but certainly not least. Make sure that you fully understand what this code and how it works. It is not going to be my phone that rings at 3am when something goes wrong. You are the one who will have to be there to support this code.
if OBJECT_ID('Something') is not null
drop table Something
create table Something
(
ID int,
Subject1 varchar(50)
)
insert Something
select 10868952, 'NUR/3110/D507' union all
select 10868952, 'NUR/3110/D512' union all
select 10868952, 'NUR/4010/D523' union all
select 10868952, 'NUR/4010/HD20' union all
select 12345, 'asdfasdf'
declare #MaxCols int
declare #StaticPortion nvarchar(2000) =
'with OrderedResults as
(
select *, ROW_NUMBER() over(partition by ID order by Subject1) as RowNum
from Something
)
select ID';
declare #DynamicPortion nvarchar(max) = '';
declare #FinalStaticPortion nvarchar(2000) = ' from OrderedResults Group by ID order by ID';
with E1(N) AS (select 1 from (values (1),(1),(1),(1),(1),(1),(1),(1),(1),(1))dt(n)),
E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
cteTally(N) AS
(
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
)
select #DynamicPortion = #DynamicPortion +
', MAX(Case when RowNum = ' + CAST(N as varchar(6)) + ' then Subject1 end) as Subject' + CAST(N as varchar(6)) + CHAR(10)
from cteTally t
where t.N <=
(
select top 1 Count(*)
from Something
group by ID
order by COUNT(*) desc
)
select #StaticPortion + #DynamicPortion + #FinalStaticPortion
--declare #SqlToExecute nvarchar(max) = #StaticPortion + #DynamicPortion + #FinalStaticPortion;
--exec sp_executesql #SqlToExecute