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sql server - Multiple Column Pivot in T-SQL

I am working with a table where there are multiple rows that I need pivoted into columns. So the pivot is the perfect solution for this, and works well when all I need is one field. I am needing to return several fields based upon the pivot. Here is the pseudo code with specifics stripped out:

SELECT 
  field1,
  [1], [2], [3], [4]
FROM
  (
  SELECT 
    field1, 
    field2, 
    (ROW_NUMBER() OVER(PARTITION BY field1 ORDER BY field2)) RowID
  FROM tblname
  ) AS SourceTable
PIVOT
  (
  MAX(field2)
  FOR RowID IN ([1], [2], [3], [4])
  ) AS PivotTable;

The above syntax works brilliantly, but what do I do when I need to get additional information found in field3, field4....?

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1 Answer

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by (71.8m points)

Rewrite using MAX(CASE...) and GROUP BY:

select 
  field1
, [1] = max(case when RowID = 1 then field2 end)
, [2] = max(case when RowID = 2 then field2 end)
, [3] = max(case when RowID = 3 then field2 end)
, [4] = max(case when RowID = 4 then field2 end)
from (
  select 
    field1
  , field2
  , RowID = row_number() over (partition by field1 order by field2)
  from tblname
  ) SourceTable
group by 
  field1

From there you can add in field3, field4, etc.


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