SQL Pivot multiple columns without forcing aggregate - sql

Question

I need to pivot out some denormalized data but it repeats so I need it to pivot out the columns and then return multiple rows.
I have a table like this
INSERT #TheTable
VALUES
('StockCode' ,'a'),
('Warehouse' ,'b'),
('TrnYear' ,'c'),
('TrnMonth' ,'d'),
('EntryDate' ,'e'),
('TrnTime' ,'f'),
('StockCode' ,'1'),
('Warehouse' ,'2'),
('TrnYear' ,'3'),
('TrnMonth' ,'4'),
('EntryDate' ,'5'),
('TrnTime' ,'6')
But when I pivot it only returns one row:
SELECT StockCode,
Warehouse,
TrnYear,
TrnMonth,
TrnTime,
EntryDate
FROM #TheTable AS src
PIVOT (MAX(column_value)
FOR COLUMN_NAME in ([TrnYear], [TrnMonth], [EntryDate], [TrnTime], [StockCode], [Warehouse])) AS piv
Result:
StockCode Warehouse TrnYear TrnMonth TrnTime EntryDate
-------------------------------------------------------------
a b c d f e
But I need it to return
StockCode Warehouse TrnYear TrnMonth TrnTime EntryDate
-------------------------------------------------------------
a b c d f e
1 2 3 4 5 6

Answer 1

You can use window functions first, then conditional aggregation:
select
max(case when column_name = 'StockCode' then column_value end) StockCode,
max(case when column_name = 'Warehouse' then column_value end) Warehouse,
max(case when column_name = 'TrnYear' then column_value end) TrnYear,
max(case when column_name = 'TrnMonth' then column_value end) TrnMonth,
max(case when column_name = 'TrnTime' then column_value end) TrnTime,
max(case when column_name = 'EntryDate' then column_value end) EntryDate
from (
select t.*,
row_number() over(partition by column_name order by column_value) rn
from #TheTable t
) t
group by rn

Answer 2

You can use ROW_NUMBER() Analytic function :
SELECT *
FROM
(
SELECT column_name, column_value,
ROW_NUMBER() OVER (PARTITION BY column_name ORDER BY column_value) AS rn
FROM #TheTable
) q
PIVOT
( MAX(column_value)
FOR column_name in ([TrnYear], [TrnMonth], [EntryDate], [TrnTime], [StockCode], [Warehouse])
) AS piv
or more dynamically, use :
DECLARE #cols AS NVARCHAR(MAX), #query AS NVARCHAR(MAX)
SET #cols = ( SELECT STRING_AGG(column_name,',')
FROM (SELECT DISTINCT column_name
FROM [#TheTable] ) q );
SET #query =
N'SELECT *
FROM
(
SELECT column_name, column_value,
ROW_NUMBER() OVER
(PARTITION BY [column_name] ORDER BY [column_value]) AS rn
FROM [#TheTable]
) f
PIVOT
(
MAX([column_value]) FOR [column_name] IN (' + #cols + N')
) AS piv '
EXEC sp_executesql #query;
Demo

Answer 3

The problem was that I needed a row_number per every group of column names. So the below worked
SELECT DISTINCT TrnYear,
TrnMonth,
EntryDate,
TrnTime,
StockCode,
Warehouse
FROM
(SELECT (ROW_NUMBER() OVER (ORDER BY dw_view_change_event_nr) - 1) / 6 + 1 AS rn,
COLUMN_NAME ,
column_value
FROM
#TheTable AS tmp) AS src PIVOT (MAX(column_value)
FOR COLUMN_NAME in ([TrnYear], [TrnMonth], [EntryDate], [TrnTime], [StockCode], [Warehouse])) AS piv