SQL Pivot with just two Columns - sql

Question

I'm trying to do a PIVOT on a table with two rows like this:
Category | Sector
---------------------------
Bulbs | DIY
Bulbs | Home
Picnic blanket | DIY
Picnic blanket | Home
Picnic blanket | Interior
Each category can have 1 or more sectors.
I'm trying to get a table like this:
Category | Sector 1 | Sector 2 | Sector 3
-------------------------------------------------
Bulbs | DIY | Home | NULL
Picnic blanket | DIY | Home | Interior
The query looks like this:
SELECT
dbo.fn_DbContent_GetTranslation(pt.Name_DbContentId, 2) 'Category'
, dbo.fn_DbContent_GetTranslation(s.Name_DbContentId, 2) 'Sector'
FROM dbo.ProductType pt
JOIN dbo.ProductTypeMandator ptm ON ptm.ProductTypeId = pt.Id
JOIN dbo.ProductTypeMandator2PortalSector ptmps ON ptmps.ProductTypeMandatorId = ptm.Id
JOIN dbo.PortalSector ps ON ps.Id = ptmps.PortalSectorId
JOIN dbo.Sector s ON s.Id = ps.SectorId
WHERE
ptmps.PortalSectorId IN (21, 18, 19)
I already did a PIVOT but with a table containing three columns where one contained the values for the headers in the pivot table. In this case the values for the header are missing so I don't know how to do it then.
Thanks for helping

Answer 1

You can solve it that way:
-- Create demo data
CREATE TABLE #cats(category nvarchar(25), sector nvarchar(25))
INSERT INTO #cats(category, sector)
VALUES (N'Bulbs',N'DIY'),
(N'Bulbs',N'Home'),
(N'Picnic blanket',N'DIY'),
(N'Picnic blanket',N'Home'),
(N'Picnic blanket',N'Interior')
SELECT *
FROM (
SELECT category, sector
FROM #cats
) as dat
PIVOT(
MAX(sector)
FOR sector IN([DIY],[Home],[Interior])
) as pvt
-- Cleanup
DROP TABLE #cats
If you want it to be named correctly as in your example, you can combine it with a named numbering:
-- Create demo data
CREATE TABLE #cats(category nvarchar(25), sector nvarchar(25))
INSERT INTO #cats(category, sector)
VALUES (N'Bulbs',N'DIY'),
(N'Bulbs',N'Home'),
(N'Picnic blanket',N'DIY'),
(N'Picnic blanket',N'Home'),
(N'Picnic blanket',N'Interior')
SELECT *
FROM (
SELECT category, sector, N'Sector '+CONVERT(nvarchar(max),DENSE_RANK() OVER(ORDER BY sector)) as rn
FROM #cats
) as dat
PIVOT(
MAX(sector)
FOR rn IN([Sector 1],[Sector 2],[Sector 3])
) as pvt
-- Cleanup
DROP TABLE #cats
And last but not least, if you want it to be dynamical:
-- Create demo data
CREATE TABLE #cats(category nvarchar(25), sector nvarchar(25))
INSERT INTO #cats(category, sector)
VALUES (N'Bulbs',N'DIY'),
(N'Bulbs',N'Home'),
(N'Picnic blanket',N'DIY'),
(N'Picnic blanket',N'Home'),
(N'Picnic blanket',N'Interior')
DECLARE #sql nvarchar(max), #cols nvarchar(max)
-- get proper column list
SELECT #cols = COALESCE(#cols + N',[' + grCols.rn + N']',N'[' + grCols.rn + N']')
FROM (
SELECT DISTINCT N'Sector '+CONVERT(nvarchar(max),DENSE_RANK() OVER(ORDER BY sector)) as rn
FROM #cats
) as grCols
SET #sql = N'
SELECT *
FROM (
SELECT category, sector, N''Sector ''+CONVERT(nvarchar(max),DENSE_RANK() OVER(ORDER BY sector)) as rn
FROM #cats
) as dat
PIVOT(
MAX(sector)
FOR rn IN('+#cols+')
) as pvt'
EXEC(#sql)
-- Cleanup
DROP TABLE #cats

Answer 2

You can do this in two ways,
One is Conditional Aggregate
;WITH cte
AS (SELECT *,
rn=Row_number()
OVER(
partition BY category
ORDER BY (SELECT NULL))
FROM yourtable)
SELECT category,
[sector 1] = Max(CASE WHEN rn = 1 THEN sector END),
[sector 2] = Max(CASE WHEN rn = 2 THEN sector END),
[sector 3] = Max(CASE WHEN rn = 3 THEN sector END)
FROM cte
GROUP BY category
Another way is using Pivot
SELECT *
FROM (SELECT *,
sector_col = 'sector '
+ Cast(Row_number()OVER(partition BY category ORDER BY (SELECT NULL)) AS VARCHAR(20))
FROM yourtable) A
PIVOT (Max(sector)
FOR sector_col IN ([sector 1],
[sector 2],
[sector 3])) piv
Note : As mentioned in comments if the sector values are not static or unknown then you may have convert the same to dynamic query