Combining columns with no common element (pivot) in SQL Server - sql-server-2005

Question

I am trying to find the best way to display some data.
My dataset looks like this:
Form var1_Day var1_WTD var1_30Day var2_Day var2_WTD var2_30Day ...
NA null null null 77 448 2581
A1 166 791 4842 null null null
A2 304 1312 8365 null null null
A3 29 113 656 null null null
I am trying to figure out how I would go about displaying the data like this:
Var Form Day WTD 30Day
var1 NA null null null
var1 A1 166 791 4842
var1 A2 304 1312 8365
var1 A3 29 113 656
var2 NA 77 448 2581
var2 A1 null null null
var2 A2 null null null
var2 A3 null null null
...
I believe I will have to use a pivot table but am not sure where to start.
Thank You,
Brad

Answer 1

While you can do this via a static pivot like the other answer, if you have a lot of columns to transform you can use a dynamic pivot:
DECLARE #colsUnPivot AS NVARCHAR(MAX),
#colsPivot AS NVARCHAR(MAX),
#colsUnPivotNull as NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
SET #colsUnPivot = stuff((select ','+quotename(C.name)
from sys.columns as C
where C.object_id = object_id('test') and
C.name like 'var%'
for xml path('')), 1, 1, '')
SET #colsUnPivotNull = stuff((select ', IsNull('+ quotename(C.name) +', 0)' + quotename(C.name)
from sys.columns as C
where C.object_id = object_id('test') and
C.name like 'var%'
for xml path('')), 1, 1, '')
SET #colsPivot = stuff((select DISTINCT ','+quotename(right((C.name), len(C.name)-5))
from sys.columns as C
where C.object_id = object_id('test') and
C.name like 'var%'
for xml path('')), 1, 1, '')
set #query
= '
SELECT var, form, '+ #colsPivot +'
FROM
(
SELECT distinct substring(field, 1, 4) var,
--field,
right((field), len(field)-5) as col,
form,
value
from
(
SELECT form, '+ #colsUnPivotNull + '
FROM test
) t1
unpivot
(
value
for field in (' + #colsUnPivot + ')
) unpvt
) x
pivot
(
sum(value)
for col in ('+ #colsPivot + ')
) p
ORDER BY var, form'
execute(#query)
See SQL Fiddle with Demo
This will get the list of columns to unpivot and the pivot at the time of execution. Then you will not have to hard code the values if you have a lot of columns.

Answer 2

Actually, you want UNPIVOT
Like so...
select SUBSTRING(t,1,4) as Var, form, day, wtd, 30day
from yourtable
unpivot ([day] for d in (var1_day,var2_day)) td
unpivot ([wtd] for w in (var1_wtd,var2_wtd)) tw
unpivot ([30day] for t in (var1_30day,var2_30day)) tt
where SUBSTRING(d,1,4) = SUBSTRING(w,1,4)
and SUBSTRING(d,1,4) = SUBSTRING(t,1,4)