Transposing an SQL Result So That One Column Goes Onto Multiple Columns

Transposing an sql result so that one column goes onto multiple columns

Consider the following demo:

CREATE TEMP TABLE qa (id int, usr int, question_id int, answer_id int);
INSERT INTO qa VALUES
 (1,1,1,1)
,(2,1,2,9)
,(3,1,3,15)
,(4,2,1,2)
,(5,2,2,12)
,(6,2,3,20);

SELECT *
FROM   crosstab('
    SELECT usr::text
          ,question_id
          ,answer_id
    FROM qa
    ORDER BY 1,2')
 AS ct (
     usr text
    ,q1 int
    ,q2 int
    ,q3 int);

Result:

 usr | q1 | q2 | q3
-----+----+----+----
 1   |  1 |  9 | 15
 2   |  2 | 12 | 20
(2 rows)

user is a reserved word. Don't use it as column name! I renamed it to usr.

You need to install the additional module tablefunc which provides the function crosstab(). Note that this operation is strictly per database.
In PostgreSQL 9.1 you can simply:

CREATE EXTENSION tablefunc;

For older version you would execute a shell-script supplied in your contrib directory. In Debian, for PostgreSQL 8.4, that would be:

psql mydb -f /usr/share/postgresql/8.4/contrib/tablefunc.sql

Transpose group of rows into multiple columns

We can try doing a pivot query with the help of ROW_NUMBER:

WITH cte AS (
    SELECT *,
        ROW_NUMBER() OVER (PARTITION BY ContactID ORDER BY CatCode, CatDesc) rn
    FROM CntTyp
)

SELECT
    ContactID,
    MAX(CASE WHEN rn = 1 THEN CatCode END) AS CatCode1,
    MAX(CASE WHEN rn = 1 THEN CatDesc END) AS CatDesc1,
    MAX(CASE WHEN rn = 2 THEN CatCode END) AS CatCode2,
    MAX(CASE WHEN rn = 2 THEN CatDesc END) AS CatDesc2,
    MAX(CASE WHEN rn = 3 THEN CatCode END) AS CatCode3,
    MAX(CASE WHEN rn = 3 THEN CatDesc END) AS CatDesc3
FROM cte
GROUP BY
    ContactID;

Simple way to transpose columns and rows in SQL?

There are several ways that you can transform this data. In your original post, you stated that PIVOT seems too complex for this scenario, but it can be applied very easily using both the UNPIVOT and PIVOT functions in SQL Server.

However, if you do not have access to those functions this can be replicated using UNION ALL to UNPIVOT and then an aggregate function with a CASE statement to PIVOT:

Create Table:

CREATE TABLE yourTable([color] varchar(5), [Paul] int, [John] int, [Tim] int, [Eric] int);

INSERT INTO yourTable
    ([color], [Paul], [John], [Tim], [Eric])
VALUES
    ('Red', 1, 5, 1, 3),
    ('Green', 8, 4, 3, 5),
    ('Blue', 2, 2, 9, 1);

Union All, Aggregate and CASE Version:

select name,
  sum(case when color = 'Red' then value else 0 end) Red,
  sum(case when color = 'Green' then value else 0 end) Green,
  sum(case when color = 'Blue' then value else 0 end) Blue
from
(
  select color, Paul value, 'Paul' name
  from yourTable
  union all
  select color, John value, 'John' name
  from yourTable
  union all
  select color, Tim value, 'Tim' name
  from yourTable
  union all
  select color, Eric value, 'Eric' name
  from yourTable
) src
group by name

See SQL Fiddle with Demo

The UNION ALL performs the UNPIVOT of the data by transforming the columns Paul, John, Tim, Eric into separate rows. Then you apply the aggregate function sum() with the case statement to get the new columns for each color.

Unpivot and Pivot Static Version:

Both the UNPIVOT and PIVOT functions in SQL server make this transformation much easier. If you know all of the values that you want to transform, you can hard-code them into a static version to get the result:

select name, [Red], [Green], [Blue]
from
(
  select color, name, value
  from yourtable
  unpivot
  (
    value for name in (Paul, John, Tim, Eric)
  ) unpiv
) src
pivot
(
  sum(value)
  for color in ([Red], [Green], [Blue])
) piv

See SQL Fiddle with Demo

The inner query with the UNPIVOT performs the same function as the UNION ALL. It takes the list of columns and turns it into rows, the PIVOT then performs the final transformation into columns.

Dynamic Pivot Version:

If you have an unknown number of columns (Paul, John, Tim, Eric in your example) and then an unknown number of colors to transform you can use dynamic sql to generate the list to UNPIVOT and then PIVOT:

DECLARE @colsUnpivot AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX),
    @colsPivot as  NVARCHAR(MAX)

select @colsUnpivot = stuff((select ','+quotename(C.name)
         from sys.columns as C
         where C.object_id = object_id('yourtable') and
               C.name <> 'color'
         for xml path('')), 1, 1, '')

select @colsPivot = STUFF((SELECT  ',' 
                      + quotename(color)
                    from yourtable t
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')


set @query 
  = 'select name, '+@colsPivot+'
      from
      (
        select color, name, value
        from yourtable
        unpivot
        (
          value for name in ('+@colsUnpivot+')
        ) unpiv
      ) src
      pivot
      (
        sum(value)
        for color in ('+@colsPivot+')
      ) piv'

exec(@query)

See SQL Fiddle with Demo

The dynamic version queries both yourtable and then the sys.columns table to generate the list of items to UNPIVOT and PIVOT. This is then added to a query string to be executed. The plus of the dynamic version is if you have a changing list of colors and/or names this will generate the list at run-time.

All three queries will produce the same result:

| NAME | RED | GREEN | BLUE |
-----------------------------
| Eric |   3 |     5 |    1 |
| John |   5 |     4 |    2 |
| Paul |   1 |     8 |    2 |
|  Tim |   1 |     3 |    9 |

SQL Transpose Multiple Columns to Rows

select Division, Period, 'Total Cost' as Description, TotalCost as Value
from MyTable
union
select Division, Period, 'Discount' as Description, Discount as Value
from MyTable
union
select Division, Period, 'Net Sales' as Description, NetSales as Value
from MyTable
union
select Division, Period, 'Net Returns' as Description, NetReturns as Value
from MyTable
union
select Division, Period, 'Gross Sales' as Description, GrossSales as Value
from MyTable
union
select Division, Period, 'Gross Returns' as Description, GrossReturns as Value
from MyTable

You can also wrap this in a view, then do a select on the view with whatever ordering or filtering that you need

Oracle SQL Transposing Only One column values as separate columns in the output

Try PIVOT

SELECT * FROM (
     SELECT
            created_date, 
            response_status,
            nvl(count,0) as count
        FROM
            t_bvs_txn_response_summary
        WHERE
            created_date > SYSDATE - 1 / 24
            AND   response_status IN (
                'successful',
                'Disconnection'
            )
)
PIVOT
(
  SUM(count)
  FOR response_status IN ('successful', 'Disconnection')
)
        ORDER BY
            1;

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