Pivot table using SQL Server 2008 R2 - sql

Question

I am getting count issue in the pivot table query using the SQL Server 2008 R2.
Example:
I have a table testrf:
CREATE TABLE testrf
(
cola INTEGER,
colb VARCHAR(10)
)
With some data:
INSERT INTO testrf VALUES(1,'x')
INSERT INTO testrf VALUES(1,'x')
INSERT INTO testrf VALUES(2,'x')
INSERT INTO testrf VALUES(3,'y')
INSERT INTO testrf VALUES(4,'y')
INSERT INTO testrf VALUES(5,'c')
INSERT INTO testrf VALUES(6,'c')
INSERT INTO testrf VALUES(7,'c')
INSERT INTO testrf VALUES(8,'d')
INSERT INTO testrf VALUES(3,'y')
INSERT INTO testrf VALUES(12,'M1')
INSERT INTO testrf VALUES(13,'L1')
INSERT INTO testrf VALUES(14,'C2')
Looks like this:
SELECT * FROM testrf;
cola colb
------------
1 x
1 x
2 x
3 y
4 y
5 c
6 c
7 c
8 d
3 y
12 M1
13 L1
14 C2
My Pivot table query:
DECLARE #cols NVARCHAR(MAX)
DECLARE #SQL NVARCHAR(MAX)
SELECT #cols = STUFF ( (SELECT DISTINCT '],[' + v.colb
FROM testrf AS v
FOR XML PATH('')), 1, 2, '') + ']'
SET #SQL = N'SELECT cola,'+ #cols +'
FROM
(SELECT v.cola,v.colb
FROM testrf AS v
GROUP BY v.cola,v.colb
) p
PIVOT
(
count(colb)
FOR colb IN ( '+ #cols + ' )
) AS pvt';
EXEC(#SQL)
Getting Result:
cola c C2 d L1 M1 x y
----------------------------------
1 0 0 0 0 0 1 0
2 0 0 0 0 0 1 0
3 0 0 0 0 0 0 1
4 0 0 0 0 0 0 1
5 1 0 0 0 0 0 0
6 1 0 0 0 0 0 0
7 1 0 0 0 0 0 0
8 0 0 1 0 0 0 0
12 0 0 0 0 1 0 0
13 0 0 0 1 0 0 0
14 0 1 0 0 0 0 0
Note: colb=x is occurred 2 times for cola=1and colb=y occurred 2 times for cola=3. Getting counting issue here.

Answer 1

You don't require the GROUP BY clause within the inner subquery (p)
DECLARE #cols NVARCHAR(MAX)
DECLARE #SQL NVARCHAR(MAX)
SELECT #cols = STUFF ( (SELECT DISTINCT ',' + QUOTENAME(v.colb)
FROM testrf AS v
FOR XML PATH('')), 1, 1, '')
SET #SQL = N'SELECT cola,'+ #cols +'
FROM
(SELECT v.cola,v.colb
FROM testrf AS v
) p
PIVOT
(
count(colb)
FOR colb IN ( '+ #cols + ' )
) AS pvt'
EXEC(#SQL)
;
I have also proposed a change to your #cols by using QUOTENAME()
From your sample data this produces the following result:
| COLA | C | C2 | D | L1 | M1 | X | Y |
|------|---|----|---|----|----|---|---|
| 1 | 0 | 0 | 0 | 0 | 0 | 2 | 0 |
| 2 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
| 3 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
| 4 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| 5 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 6 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 7 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 8 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| 12 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| 13 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| 14 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
See this at SQLfiddle