SQL Server - PIVOT - two columns into rows

Question

I saw many questions about PIVOT for a single column, each question more complex than other, however, I could not find anything like what I need.

To be honest, I don't even know if pivot will help me in this situation.

Let's say I have this data on my source table:

SELECT '1' as 'RowId', 'RandomName1' as 'First', 'RandomLast1' as 'Last'
UNION
SELECT '2' as 'RowId', 'RandomName2' as 'First', 'RandomLast2' as 'Last'
UNION
SELECT '3' as 'RowId', 'RandomName3' as 'First', 'RandomLast3' as 'Last'
UNION
SELECT '4' as 'RowId', 'RandomName4' as 'First', 'RandomLast4' as 'Last'
UNION
SELECT '5' as 'RowId', 'RandomName5' as 'First', 'RandomLast5' as 'Last'

Maximum of 5 rows with the first name and last name. The value of the columns First and Last will be random.

RowId First       Last
----- ----------- -----------
1     RandomName1 RandomLast1
2     RandomName2 RandomLast2
3     RandomName3 RandomLast3
4     RandomName4 RandomLast4
5     RandomName5 RandomLast5

I was trying to pivot this data to something like this:

First1      Last1       First2      Last2       First3      Last3       First4      Last4       First5      Last5
----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- -----------
RandomName1 RandomLast1 RandomName2 RandomLast2 RandomName3 RandomLast3 RandomName4 RandomLast4 RandomName5 RandomLast5

For example: I don't have any problem if columns First5 and Last5 are NULL because there are only 4 rows.

First1      Last1       First2      Last2       First3      Last3       First4      Last4       First5      Last5
----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- ----------- -----------
RandomName1 RandomLast1 RandomName2 RandomLast2 RandomName3 RandomLast3 RandomName4 RandomLast4 NULL        NULL

Can anyone give me a little help? Thanks.

---

Solution based on Sheela K R answers:

SELECT 
    MAX(First1) as 'First1',  MAX(Last1) as 'Last1',
    MAX(First2) as 'First2',  MAX(Last2) as 'Last2',
    MAX(First3) as 'First3',  MAX(Last3) as 'Last3',
    MAX(First4) as 'First4',  MAX(Last4) as 'Last4',
    MAX(First5) as 'First5',  MAX(Last5) as 'Last5'
FROM
(
    SELECT 
        CASE WHEN RowId = 1 THEN [First] END as 'First1',
        CASE WHEN RowId = 1 THEN [Last] END as 'Last1',
        CASE WHEN RowId = 2 THEN [First] END as 'First2',
        CASE WHEN RowId = 2 THEN [Last] END as 'Last2',
        CASE WHEN RowId = 3 THEN [First] END as 'First3',
        CASE WHEN RowId = 3 THEN [Last] END as 'Last3',
        CASE WHEN RowId = 4 THEN [First] END as 'First4',
        CASE WHEN RowId = 4 THEN [Last] END as 'Last4',
        CASE WHEN RowId = 5 THEN [First] END as 'First5',
        CASE WHEN RowId = 5 THEN [Last] END as 'Last5'
    FROM
    (
        SELECT '1' as 'RowId', 'RandomName1' as 'First', 'RandomLast1' as 'Last'
        UNION SELECT '2' as 'RowId', 'RandomName2' as 'First', 'RandomLast2' as 'Last'
        UNION SELECT '3' as 'RowId', 'RandomName3' as 'First', 'RandomLast3' as 'Last'
        UNION SELECT '4' as 'RowId', 'RandomName4' as 'First', 'RandomLast4' as 'Last'
        --UNION SELECT '5' as 'RowId', 'RandomName5' as 'First', 'RandomLast5' as 'Last'
    ) test
) test2

Answer 1

There are a few different ways that you can get the result that you want. Similar to @Sheela K R's answer you can use an aggregate function with a CASE expression but it can be written in a more concise way:

select 
  max(case when rowid = 1 then first end) First1,
  max(case when rowid = 1 then last end) Last1,
  max(case when rowid = 2 then first end) First2,
  max(case when rowid = 2 then last end) Last2,
  max(case when rowid = 3 then first end) First3,
  max(case when rowid = 3 then last end) Last3,
  max(case when rowid = 4 then first end) First4,
  max(case when rowid = 4 then last end) Last4,
  max(case when rowid = 5 then first end) First5,
  max(case when rowid = 5 then last end) Last5
from yourtable;

See SQL Fiddle with Demo.

This could also be written using the PIVOT function, however since you want to pivot multiple columns then you would first want to look at unpivoting your First and Last columns.

The unpivot process will convert your multiple columns into multiple rows of data. You did not specify what version of SQL Server you are using but you can use a SELECT with UNION ALL with CROSS APPLY or even the UNPIVOT function to perform the first conversion:

select col = col + cast(rowid as varchar(10)), value
from yourtable
cross apply 
(
  select 'First', First union all
  select 'Last', Last
) c (col, value)

See SQL Fiddle with Demo. This converts your data into the format:

|    COL |       VALUE |
|--------|-------------|
| First1 | RandomName1 |
|  Last1 | RandomLast1 |
| First2 | RandomName2 |
|  Last2 | RandomLast2 |

Once the data is in multiple rows, then you can easily apply the PIVOT function:

select First1, Last1, 
  First2, Last2,
  First3, Last3, 
  First4, Last4, 
  First5, Last5
from
(
  select col = col + cast(rowid as varchar(10)), value
  from yourtable
  cross apply 
  (
    select 'First', First union all
    select 'Last', Last
  ) c (col, value)
) d
pivot
(
  max(value)
  for col in (First1, Last1, First2, Last2,
              First3, Last3, First4, Last4, First5, Last5)
) piv;

See SQL Fiddle with Demo

Both give a result of:

|      FIRST1 |       LAST1 |      FIRST2 |       LAST2 |      FIRST3 |       LAST3 |      FIRST4 |       LAST4 |      FIRST5 |       LAST5 |
|-------------|-------------|-------------|-------------|-------------|-------------|-------------|-------------|-------------|-------------|
| RandomName1 | RandomLast1 | RandomName2 | RandomLast2 | RandomName3 | RandomLast3 | RandomName4 | RandomLast4 | RandomName5 | RandomLast5 |

Answer 2

Try something like this

CREATE TABLE #Table1
    ([uid] int, [name] varchar(4), [diseaseid] int, [intensity] varchar(4))
;

INSERT INTO #Table1
    ([uid], [name], [diseaseid], [intensity])
VALUES    (1, 'xxxx', 2, 'low')
    (1, 'xxxx', 1, 'high'),

;

SELECT MAX([uid]) AS [uid]
       ,MAX([name]) AS [name]
       ,MAX([diseaseid1]) AS [diseaseid1]
       ,MAX([intensity1]) AS [intensity1]
       ,MAX([diseaseid2]) AS [diseaseid2]
       ,MAX([intensity2]) [intensity2]
FROM 
(
    SELECT [uid], [name]
    , CASE WHEN rn=2 THEN NULL ELSE [diseaseid] END AS [diseaseid1]
    , CASE WHEN rn=2 THEN NULL ELSE [intensity] END AS [intensity1]
    , CASE WHEN rn=1 THEN NULL ELSE [diseaseid] END AS [diseaseid2]
    , CASE WHEN rn=1 THEN NULL ELSE [intensity] END AS [intensity2]
    FROM
    (
        SELECT [uid], [name], [diseaseid], [intensity], 
        ROW_NUMBER() OVER(PARTITION BY [uid] ORDER BY Name) AS rn
        FROM #Table1
    ) T
) T
GROUP BY [uid], [name]