Getting the column name that holds the maximum value of a row - sql

Question

I have generated an extensive view which simulates certain occurrences based on different statistic models. These models are defined in each column header by a number and the maximum value of a row is the best model.
The table generated looks (partially) as follows;
+--------+----+------+------+------+------+------+------+
| Number | LI | PHSE | 0505 | 0506 | 0507 | 0508 | 0509 | [...] etc.
+--------+----+------+------+------+------+------+------+
| 100254 | 2 | M1 | 44 | 46 | 45 | 44 | 44 |
| 100254 | 2 | M2 | 36 | 36 | 35 | 37 | 37 |
| 100254 | 2 | M3 | 5 | 5 | 5 | 5 | 5 |
| 100254 | 2 | R1 | 34 | 36 | 37 | 37 | 37 |
| 100254 | 2 | R2 | 41 | 41 | 40 | 41 | 41 |
| 100329 | 1 | M1 | 37 | 38 | 38 | 38 | 39 |
| 100329 | 1 | M2 | 31 | 29 | 28 | 29 | 29 |
| 100329 | 1 | M3 | 6 | 6 | 6 | 6 | 6 |
| 100329 | 1 | R1 | 29 | 29 | 29 | 30 | 30 |
| 100329 | 1 | R2 | 25 | 26 | 26 | 27 | 26 |
+--------+----+------+------+------+------+------+------+
[...] etc.
Now I want to find the highest value in each row and display the corresponding column name as such;
| Number | LI | PHSE | MAXCOL |
+--------+----+------+--------+
| 100254 | 2 | M1 | 0506 |
| 100254 | 2 | M2 | 0508 |
| 100254 | 2 | M3 | 0505 |
| 100254 | 2 | R1 | 0507 |
| 100254 | 2 | R2 | 0505 |
+--------+----+------+--------+
[...] etc.
This is derived from 100254 - 2 - M1 largest value 46 occurring in column 0506, etc.
I've been toying around with PIVOT functions but no success there. I've also looked for an Index/Match equivalent like in Excel but since I can't refer to column headers as values this obviously won't work (and haven't found such function either).
Any help would be hugely appreciated.
UPDATE per Damien's comment:
An excerpt from the code that led to this:
SELECT DISTINCT sub2.Number, sub2.LI, sub2.PHSE
, sum(sub2.[0505]) over (partition by sub2.Number, sub2.LI, sub2.PHSE) as '0505'
, sum(sub2.[0506]) over (partition by sub2.Number, sub2.LI, sub2.PHSE) as '0506'
[...] etc. /*64 rows*/
FROM
(SELECT DISTINCT sub.*
, CASE WHEN sub.MF > sub.[5PAV] - sub.[5PSTDEV] THEN 1 ELSE 0 END AS '0505'
, CASE WHEN sub.MF > sub.[5PAV] - sub.[6PSTDEV] THEN 1 ELSE 0 END AS '0506'
[...] etc. /*64 rows*/
FROM
(SELECT DISTINCT ra.*
, sum(ra.qtyr) OVER (partition BY ra.Number, ra.LI, ra.PHSE ORDER BY (ra.Number) rows BETWEEN 5 preceding AND 1 preceding) /
sum(ra.qtyu) OVER (partition BY ra.Number, ra.LI, ra.PHSE ORDER BY (ra.Number) rows BETWEEN 5 preceding AND 1 preceding) AS '5PAV'
, sum(ra.qtyr) OVER (partition BY ra.Number, ra.LI, ra.PHSE ORDER BY (ra.Number) rows BETWEEN 6 preceding AND 1 preceding) /
sum(ra.qtyu) OVER (partition BY ra.Number, ra.LI, ra.PHSE ORDER BY (ra.Number) rows BETWEEN 6 preceding AND 1 preceding) AS '6PAV'
[...] etc. /*8 rows*/
, stdev(ra.MF) OVER (partition BY ra.Number, ra.LI, ra.PHSE ORDER BY (ra.Number) rows BETWEEN 4 preceding AND CURRENT row) AS '5PSTDEV'
, stdev(ra.MF) OVER (partition BY ra.Number, ra.LI, ra.PHSE ORDER BY (ra.Number) rows BETWEEN 5 preceding AND CURRENT row) AS '6PSTDEV'
[...] etc. /*8 rows*/
FROM ra
) AS sub
) AS sub2
No doubt that this may be one of the most ineffective uses of SQL, but time-pressure and inexperience made me write it this way.
Any suggestions to change this code and achieve the desired table result more efficiently would be much appreciated too.
EDIT per Anton's answer;
The above code summarized as pvt continues as follows;
SELECT Number, LI, PHSE, combo, hitrate
FROM (...) AS pvt
UNPIVOT
(Hitrate FOR Combo IN (
[0505],
[0506],
[...] etc.)) AS upvt
Great solution to an inelegant problem.

Answer 1

You need to use UNPIVOT, not PIVOT
https://msdn.microsoft.com/en-us/library/ms177410.aspx
If the number of columns is variable, you have to use dynamic sql to construct the list of columns

Answer 2

If you want to see all MAXCOL (equal columns) try this:
CREATE TABLE table1 (
Number NUMERIC(10),
LI numeric(10),
PHSE NVARCHAR(10),
[0505] numeric(10),
[0506] numeric(10),
[0507] numeric(10),
[0508] numeric(10),
[0509] numeric(10))
INSERT INTO table1 VALUES(100254,2,'M1',44 ,46 ,45 ,44,44)
INSERT INTO table1 VALUES(100254,2,'M2',36,36,35,37,37)
INSERT INTO table1 VALUES(100254,2,'M3',5,5,5,5,5)
INSERT INTO table1 VALUES(100254,2,'R1',34,36,37,37,37)
INSERT INTO table1 VALUES(100254,2, 'R2',41,41,40,41,41)
INSERT INTO table1 VALUES(100329,1, 'M1',37,38,38,38,39)
INSERT INTO table1 VALUES(100329,1, 'M2',31,29,28,29,29)
INSERT INTO table1 VALUES(100329,1, 'M3',6,6,6,6,6)
INSERT INTO table1 VALUES(100329,1, 'R1',29,29,29,30,30)
INSERT INTO table1 VALUES(100329,1, 'R2',25,26,26,27,26)
SELECT *
INTO #UNPIVOT
FROM table1
UNPIVOT ( num
FOR MAXCOL IN ([0505],[0506],[0507],[0508],[0509])) AS k
SELECT A.Number,A.LI,A.PHSE,A.num,B.MAXCOL FROM
(SELECT number,LI,PHSE,MAX(num) AS num FROM #UNPIVOT GROUP BY number,LI,PHSE) A
LEFT JOIN
(SELECT * FROM #UNPIVOT) B ON A.num=B.num AND A.Number=B.Number AND A.LI=B.LI AND A.PHSE=B.PHSE

Answer 3

I would use CROSS APPLY as follows:
WITH Src AS
(
SELECT * FROM (VALUES
(100254, 2, 'M1', 44, 46, 45, 44, 44),
(100254, 2, 'M2', 36, 36, 35, 37, 37),
(100254, 2, 'M3', 5, 5, 5, 5, 5),
(100254, 2, 'R1', 34, 36, 37, 37, 37),
(100254, 2, 'R2', 41, 41, 40, 41, 41),
(100329, 1, 'M1', 37, 38, 38, 38, 39),
(100329, 1, 'M2', 31, 29, 28, 29, 29),
(100329, 1, 'M3', 6, 6, 6, 6, 6),
(100329, 1, 'R1', 29, 29, 29, 30, 30),
(100329, 1, 'R2', 25, 26, 26, 27, 26)) T(Number, LI, PHSE, [0505], [0506], [0507], [0508], [0509])
)
SELECT Number, LI, PHSE, MaxCol
FROM Src
CROSS APPLY (SELECT TOP 1 * FROM (VALUES
('0505', [0505]),
('0506', [0506]),
('0507', [0507]),
('0508', [0508]),
('0509', [0509])
) T(MaxCol, Val) ORDER BY Val DESC) Q
Note that equal columns may be chosen randomly unless some additional value is specified, i.e. MaxCol.
Update
You need dynamic query, like following one:
DECLARE #sql nvarchar(MAX) =
'SELECT Number, LI, PHSE, MaxCol
FROM Src
CROSS APPLY (SELECT TOP 1 * FROM (VALUES' +STUFF(
(SELECT ',(', QUOTENAME(name, '''')+','+QUOTENAME(name)+')'
FROM sys.columns
WHERE object_id=OBJECT_ID('Src') AND name NOT IN ('Number', 'LI', 'PHSE')
FOR XML PATH('')), 1, 1, '')+') T(MaxCol, Val) ORDER BY Val DESC) Q';
EXEC(#sql);
Src is your table name, replace it accordingly.

Answer 4

You can use UNPIVOT and CROSS APPLY.
With this solution you don't have to specify all the columns multiple times.
Source data:
CREATE TABLE Student
([Name] varchar(5), [Maths] int, [Science] int, [English] int)
;
INSERT INTO Student
([Name], [Maths], [Science], [English])
VALUES
('Tilak', 90, 40, 60),
('Raj', 30, 50, 70)
;
Solution:
with foo as (
select name, subject, marks
from student
unpivot
(
marks
for subject in (Science, Maths, English)
) u
)
select distinct f1.name, f2.subject
from foo f1
cross apply (
select top 1 name, subject
from foo
where f1.Name = Name
order by Marks desc) f2
Result:
--------------------------------------------------
| Name | Subject
--------------------------------------------------
| Tilak | Maths
--------------------------------------------------
| Raj | Science
--------------------------------------------------
http://sqlfiddle.com/#!18/780cd8/5