srobinson 596 (11/12/2012)
So I have been reading up on pivot tables because I thought that was the direction I needed to go in. However - I am not aggregating any data. So let me first present my scenario - after that any insight would be appreciated.I am creating a report for items that have an id as well as a material description. An item can exist multiple times with different types of material. Also - an item can have no more than 5 materials. For example:
item ID Material
337139Ring-Band
337139Ring-Artisan
337139GOLD
337156Acc-Tokens
337174Ring-Gemstone
337174Ring-Artisan
337174SILVER
337183Ring-Band
337183MIXED METAL
337184Earrings-Hoop
337184MIXED METAL
337194Earrings-Dangle
337194SILVER
What I am looking to do is invert the data - so an item would only show up once followed by up to 5 materials.
item id Material 1 Material 2 Material 3 Material 4 Material 5
337139 Ring-Band Ring-Band Ring-Artisan
337156 Acc-Tokens
337174 Ring-Gemstone Ring-Artisan SILVER
Is there a way to transpose this then? Any help would be appreciated.
I have created some insert statements for the data:
create table materials (item_id int, materials varchar(35))
insert into materials values (337139,'Ring-Band');
insert into materials values (337139,'Ring-Artisan') ;
insert into materials values (337139,'GOLD');
insert into materials values (337156,'Acc-Tokens');
insert into materials values (337174,'Ring-Gemstone');
insert into materials values (337174,'Ring-Artisan');
insert into materials values (337174,'SILVER');
insert into materials values (337183,'Ring-Band');
insert into materials values (337183,'MIXED METAL');
insert into materials values (337184,'Earrings-Hoop');
insert into materials values (337184,'MIXED METAL');
insert into materials values (337194,'Earrings-Dangle');
insert into materials values (337194,'SILVER');
Nicely done. I absolutely love it when someone takes the time to help me help them with readily consumable test data.
The following code will do what you ask. Keep in mind that an aggregate can be an aggregate of just one element. 😉 It employs what CapnHector was talking about.
WITH
cteEnumerateMaterials AS
(
SELECT item_id, materials,
Material# = ROW_NUMBER() OVER (PARTITION BY item_id ORDER BY materials)
FROM materials
)
SELECT [Item ID] = item_id,
[Material 1] = MAX(CASE WHEN Material# = 1 THEN materials ELSE '' END),
[Material 2] = MAX(CASE WHEN Material# = 2 THEN materials ELSE '' END),
[Material 3] = MAX(CASE WHEN Material# = 3 THEN materials ELSE '' END),
[Material 4] = MAX(CASE WHEN Material# = 4 THEN materials ELSE '' END),
[Material 5] = MAX(CASE WHEN Material# = 5 THEN materials ELSE '' END)
FROM cteEnumerateMaterials
GROUP BY item_id
;
--Jeff Moden
Change is inevitable... Change for the better is not.