trying to flatten rows into columns

Question

I have a group of rows in a table that have an id. I am trying to flatten it out in rows with multiple column. I am almost certain I have done this with a cte and maybe partition.

I have used cte's to delete duplicate data and I thought I has done something similar to what I am trying to accomplish here. I was able to come up with workable solution (listed below) but still feel like a more elegant solution should be available.

CREATE TABLE #MyTable ( RowID int , field VARCHAR(10), value  VARCHAR(10))  

INSERT INTO #MyTable ( RowID, field, value ) VALUES  ( 1, 'first', 'neil' )

INSERT INTO #MyTable ( RowID, field, value ) VALUES  ( 2, 'first', 'bob'  )

INSERT INTO #MyTable ( RowID, field, value ) VALUES  ( 3, 'first', 'tom'  )

INSERT INTO #MyTable ( RowID, field, value ) VALUES  ( 1, 'last', 'young' )

INSERT INTO #MyTable ( RowID, field, value ) VALUES  ( 2, 'last', 'dylan' )

INSERT INTO #MyTable ( RowID, field, value ) VALUES  ( 3, 'last', 'petty' )

SELECT * FROM #mytable

--trying to accomplish this with cte/partition:

SELECT rowid, 
   [first] = (Select value FROM #mytable where field = 'first' and rowid = t.rowid), 
   [last] = (Select value FROM #mytable where field = 'last' and rowid = t.rowid)
FROM #mytable t
GROUP BY rowid

Answer 1

This data transformation is known as a PIVOT. In SQL Server 2005+ there is a function that will perform this process. :

select *
from
(
  SELECT * 
  FROM mytable
) src
pivot
(
  max(value)
  for field in (first, last)
) piv

See SQL Fiddle with Demo.

Or you can use an aggregate function with a CASE expression:

select rowid,
  max(case when field = 'first' then value end) first,
  max(case when field = 'last' then value end) last
from MyTable
group by rowid

See SQL Fiddle with Demo.

You can also use multiple joins on your table:

select t1.rowid,
  t1.value first,
  t2.value last
from mytable t1
left join mytable t2
  on t1.rowid = t2.rowid
  and t2.field = 'last'
where t1.field = 'first'

See SQL Fiddle with Demo

The result for all versions is the same:

| ROWID | FIRST |  LAST |
-------------------------
|     1 |  neil | young |
|     2 |   bob | dylan |
|     3 |   tom | petty |