SQL complex dynamic Pivoting 2 - sql

Question

Hi I am trying in SQL Server the pivoting for the following table
REFID | COL1 | COL2 | Sequence
1 abc cde 1
1 lmn rst 2
1 kna asg 3
2 als zkd 2
2 zpk lad 1
I want the output as
REFID | 1COL1 | 2COL1 | 3COL1 |1COL2|2COL2|3COL2
1 abc lmn kna cde rst asg
2 zpk als null lad zkd null
The number of columns in the original table are known but the number of rows are not known. Can any one help

Answer 1

If you want to include the sequence number as part of your column names, then you will still need to unpivot your col1 and col2 columns first, then apply the pivot. The difference is that you will concatenate the sequence number to your column names created during the unpivot process.
For a known number of values the query would be:
select REFID,
[1col1], [2col1], [3col1],
[1col2], [2col2], [3col2]
from
(
select REFID,
col = cast(Sequence as varchar(10))+ col, value
from yourtable
cross apply
(
select 'COL1', col1 union all
select 'COL2', col2
) c (col, value)
) d
pivot
(
max(value)
for col in ([1col1], [2col1], [3col1],
[1col2], [2col2], [3col2])
) piv
order by refid;
Then if you have an unknown number the dynamic SQL version will be:
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT ',' + QUOTENAME(cast(Sequence as varchar(10))+ col)
from yourtable
cross apply
(
select 'Col1', 1 union all
select 'Col2', 2
) c(col, so)
group by Sequence, col, so
order by so, sequence
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT refid, ' + #cols + '
from
(
select REFID,
col = cast(Sequence as varchar(10))+ col, value
from yourtable
cross apply
(
select ''COL1'', col1 union all
select ''COL2'', col2
) c (col, value)
) x
pivot
(
max(value)
for col in (' + #cols + ')
) p
order by refid'
execute sp_executesql #query;