Select every 10 row as a new column in sql server - sql

Question

I have a SQL Table with data as shown,
Item Qty
------------
A1 59
A2 76
A3 86
A1 12
A2 17
A3 15
A1 23
A2 39
A3 07
Here we can see Item is repeated.So, i would like to group the records by Item.
I want to get the output table look like below
Item Qty1 Qty2 qty3
----------------------------------
A1 59 12 23
A2 76 17 39
A3 86 15 07

Answer 1

Use pivot with ranking function ROW_NUMBER:
WITH CTE
AS
(
SELECT
Item, QTy, ROW_NUMBER() OVER(PARTITION BY ITem ORDER BY Item) AS RN
FROM tablename
)
SELECT Item, [1] AS Qty1, [2] AS Qty2, [3] AS Qty3
FROM CTE
PIVOT
(
SUM(Qty)
FOR rn IN([1], [2], [3])
) AS p;
demo
Results:
| Item | Qty1 | Qty2 | Qty3 |
|------|------|------|------|
| A1 | 59 | 12 | 23 |
| A2 | 39 | 17 | 76 |
| A3 | 86 | 15 | 7 |
If these quantities are not fixed and they are not 3 always, you need to do it dynamically like this:
DECLARE #cols AS NVARCHAR(MAX);
DECLARE #query AS NVARCHAR(MAX);
DECLARE #colNames AS NVARCHAR(MaX);
select #cols = STUFF((SELECT distinct ',' +
QUOTENAME(CAST(RN AS NVARCHAR(10)))
FROM
(
SELECT
Item, QTy, ROW_NUMBER() OVER(PARTITION BY ITem ORDER BY Item) AS RN
FROM tablename ) as t
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
, 1, 1, '');
select #colNames = STUFF((SELECT distinct ',' +
'[' + CAST(RN AS NVARCHAR(10)) + '] AS Qty' +
CAST(RN AS NVARCHAR(10))
FROM
(
SELECT
Item, QTy, ROW_NUMBER() OVER(PARTITION BY ITem ORDER BY Item) AS RN
FROM tablename ) as t
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
, 1, 1, '');
SELECT #query = 'WITH CTE
AS
(
SELECT
Item, QTy, ROW_NUMBER() OVER(PARTITION BY ITem ORDER BY Item) AS RN
FROM tablename
)
SELECT Item,' + #colNames + '
FROM CTE
PIVOT
(
SUM(Qty)
FOR rn IN(' + #cols + ')
) AS p;';
execute(#query);
demo

Answer 2

You can use pivot as below:
Select * from (
Select *, Qtys = Concat('Qty', Row_Number() over(partition by Item order by Item))
from #itemdata
) a
pivot (max(qty) for qtys in ([Qty1],[Qty2],[Qty3])) p
For dynamic list you can query as below:
Declare #cols1 varchar(max)
Declare #query nvarchar(max)
Select #cols1 = stuff((select top (select max(cnt) from (select count(*) cnt from #itemdata group by item ) a) ','+
QuoteName(Concat('Qty', Row_Number() over(order by (select Null)))) from
master..spt_values c1, master..spt_values c2 for xml path('')),1,1,'')
Select #query = ' Select * from (
Select *, Qtys = Concat(''Qty'', Row_Number() over(partition by Item order by Item))
from #itemdata
) a
pivot (max(qty) for qtys in (' + #cols1 + ')) p '
Exec sp_executesql #query