Need to select table data into distinct columns based on a date in a row - sql

Question

I am not sure what I need here, looks sort of like I could use a pivot but I don't think it's that complicated and would like to avoid pivot if I can as I haven't used it much (er, at all).
I have data like this:
ID score notes CreateDate
1661 9.2 8.0 on Sept 2010 7/22/2010
1661 7.6 11/4/2010
1661 7.9 6/10/2011
1661 8.3 9/28/2011
1661 7.9 1/20/2012
I want to organize all that data on to one row with the oldest date being first and then use the next oldest date, then next oldest...until I use 4 or 5 dates. So the end result would look something like this:
ID score1 notes1 date1 score2 notes2 date2 score3 notes3 date3 score4 notes4 date4
1661 9.2 8.0 on Sept 2010 7/22/2010 7.6 blah 11/4/2010 7.9 blah2 6/10/2011 8.3 blah3 9/28/2011

Answer 1

PIVOT would be tricky in this situation, since you have more than one column per test (PIVOT works well if you only wanted to show Score1, Score2, Score3, etc). Fortunately, you can create a simple (if long-winded) solution with CASE statements:
select
ID,
max(case when RowNum = 1 then Score else null end) as Score1,
max(case when RowNum = 1 then Notes else null end) as Notes1,
max(case when RowNum = 1 then CreateDate else null end) as Date1,
max(case when RowNum = 2 then Score else null end) as Score2,
max(case when RowNum = 2 then Notes else null end) as Notes2,
max(case when RowNum = 2 then CreateDate else null end) as Date2,
max(case when RowNum = 3 then Score else null end) as Score3,
max(case when RowNum = 3 then Notes else null end) as Notes3,
max(case when RowNum = 3 then CreateDate else null end) as Date3,
max(case when RowNum = 4 then Score else null end) as Score4,
max(case when RowNum = 4 then Notes else null end) as Notes4,
max(case when RowNum = 4 then CreateDate else null end) as Date4,
max(case when RowNum = 5 then Score else null end) as Score5,
max(case when RowNum = 5 then Notes else null end) as Notes5,
max(case when RowNum = 5 then CreateDate else null end) as Date5
from
(
select
*, row_number() over (partition by ID order by CreateDate) as RowNum
from
mytable
) tt
group by
ID
This is hard-coded to cover 5 tests. It will be OK with less, but won't display a 6th. You can obviously create more CASE statements to handle more tests.

Answer 2

Just because I love pivots, I will show you how this can be done using the PIVOT function. In order to get the result with the PIVOT function you will first want to UNPIVOT your multiple columns score, notes and createdate. The unpivot process will convert the multiple columns into multiple rows.
Since you are using SQL Server 2008 you can use CROSS APPLY to unpivot your data, the first part of the query will be similar to:
;with cte as
(
select id, score, notes, createdate,
row_number() over(partition by id order by createdate) seq
from yourtable
)
select id, col, value
from
(
select t.id,
col = col + cast(seq as varchar(10)),
value
from cte t
cross apply
(
values
('score', cast(score as varchar(10))),
('notes', notes),
('date', convert(varchar(10), createdate, 120))
) c (col, value)
) d;
See SQL Fiddle with Demo. Doing this gets your data in the format:
| ID | COL | VALUE |
| 1661 | score1 | 9.20 |
| 1661 | notes1 | 8.0 on Sept 2010 |
| 1661 | date1 | 2010-07-22 |
| 1661 | score2 | 7.60 |
| 1661 | notes2 | (null) |
| 1661 | date2 | 2010-11-04 |
| 1661 | score3 | 7.90 |
Now you can apply the PIVOT function:
;with cte as
(
select id, score, notes, createdate,
row_number() over(partition by id order by createdate) seq
from yourtable
)
select id, col, value
from
(
select t.id,
col = col + cast(seq as varchar(10)),
value
from cte t
cross apply
(
values
('score', cast(score as varchar(10))),
('notes', notes),
('date', convert(varchar(10), createdate, 120))
) c (col, value)
) d
pivot
(
max(value)
for col in (score1, notes1, date1, score2, notes2, date2,
score3, notes3, date3, score4, notes4, date4,
score5, notes5, date5)
) piv;
See SQL Fiddle with Demo.
Then if you were going to have an unknown number of values for each id, you could implement dynamic SQL to get the result:
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT ',' + QUOTENAME(col + cast(seq as varchar(10)))
from
(
select row_number() over(partition by id order by createdate) seq
from yourtable
) d
cross apply
(
select 'score', 1 union all
select 'notes', 2 union all
select 'date', 3
) c (col, so)
group by seq, col, so
order by seq, so
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT id, ' + #cols + '
from
(
select t.id,
col = col + cast(seq as varchar(10)),
value
from
(
select id, score, notes, createdate,
row_number() over(partition by id order by createdate) seq
from yourtable
) t
cross apply
(
values
(''score'', cast(score as varchar(10))),
(''notes'', notes),
(''date'', convert(varchar(10), createdate, 120))
) c (col, value)
) x
pivot
(
max(value)
for col in (' + #cols + ')
) p '
execute sp_executesql #query;
See SQL Fiddle with Demo. Both versions give the result:
| ID | SCORE1 | NOTES1 | DATE1 | SCORE2 | NOTES2 | DATE2 | SCORE3 | NOTES3 | DATE3 | SCORE4 | NOTES4 | DATE4 | SCORE5 | NOTES5 | DATE5 |
| 1661 | 9.20 | 8.0 on Sept 2010 | 2010-07-22 | 7.60 | (null) | 2010-11-04 | 7.90 | (null) | 2011-06-10 | 8.30 | (null) | 2011-09-28 | 7.90 | (null) | 2012-01-20 |