Pivot table with non-cardinal values

Question

I have a table that looks like

Test   Reader    Result
1      John      1.6
1      Jack      5.2
2      Ursula    2.5
3      Albert    3.0
2      Jack      5         


        

Answer 1

See my comment above. I tried to convert for your table (T1):

 WITH TX AS (SELECT TEST, READER, RESULT, ROW_NUMBER() OVER (PARTITION BY TEST ORDER BY READER) AS RN
            FROM T1
            )
SELECT T0.TEST
    , TT1.READER AS READER_1
    , TT1.RESULT AS RESULT_1
    , TT2.READER AS READER_2
    , TT2.RESULT AS RESULT_2
    , TT3.READER AS READER_3
    , TT3.RESULT AS RESULT_3
FROM (SELECT DISTINCT TEST FROM T1) AS T0
LEFT JOIN TX TT1 ON T0.TEST = TT1.TEST AND TT1.RN=1
LEFT JOIN TX TT2 ON T0.TEST = TT2.TEST AND TT2.RN=2
LEFT JOIN TX TT3 ON T0.TEST = TT3.TEST AND TT3.RN=3;

Answer 2

A solution that does not require multiple self-joins:

You can PIVOT on the result of the ROW_NUMBER() analytic function to get your desired output:

SELECT *
FROM   (
  SELECT t.*,
         ROW_NUMBER() OVER ( PARTITION BY test ORDER BY ROWNUM ) AS rn
  FROM   your_table t
)
PIVOT ( MAX( Reader ) AS reader, MAX( result ) AS result FOR rn IN ( 1, 2, 3 ) );

Output:

TEST 1_READER 1_RESULT 2_READER 2_RESULT 3_READER 3_RESULT
---- -------- -------- -------- -------- -------- --------
   1 John          1.6 Jack          5.2
   2 Ursula        2.5 Jack          5.1
   3 Albert        3.0

Or, just using aggregation functions:

SELECT test,
       MAX( CASE rn WHEN 1 THEN reader END ) AS reader_1,
       MAX( CASE rn WHEN 1 THEN result END ) AS result_1,
       MAX( CASE rn WHEN 2 THEN reader END ) AS reader_2,
       MAX( CASE rn WHEN 2 THEN result END ) AS result_2,
       MAX( CASE rn WHEN 3 THEN reader END ) AS reader_3,
       MAX( CASE rn WHEN 3 THEN result END ) AS result_3
FROM   (
  SELECT t.*,
         ROW_NUMBER() OVER ( PARTITION BY test ORDER BY ROWNUM ) AS rn
  FROM   your_table t
)
GROUP BY test;