How to apply pivot in below scenarios - sql

Question

I have below table
Name Month Year Count
----------------------------
xxx 12 2012 24
xxx 1 2013 42
xxx 2 2013 23
yyy 12 2012 34
yyy 1 2013 12
yyy 2 2013 54
I would like to convert it into below format,
Name Dec-12 Jan-13 Feb-13
--------------------------------
xxx 24 42 23
yyy 34 12 54
How to apply pivot?

Answer 1

Since you are using SQL Server there are several ways that you can pivot the data from rows into columns.
If your values are limited or you have a known number of values, then you can hard-code the values with a static pivot:
select name, [Dec_12], [Jan_13], [Feb_13]
from
(
select name,
left(datename(month, dateadd(month, month, 0) -1), 3) +'_'+right(cast(year as varchar(4)), 2) MY,
[count]
from yourtable
) src
pivot
(
sum(count)
for my in ([Dec_12], [Jan_13], [Feb_13])
) piv;
See SQL Fiddle with Demo.
Now, if you have an unknown number of values, then you will need to implement dynamic SQL to generate the result:
DECLARE #cols AS NVARCHAR(MAX),
#query AS NVARCHAR(MAX)
select #cols = STUFF((SELECT ',' + QUOTENAME(my)
from
(
select left(datename(month, dateadd(month, month, 0) -1), 3) +'_'+right(cast(year as varchar(4)), 2) my,
CAST(
CAST(year AS VARCHAR(4)) +
RIGHT('0' + CAST(month AS VARCHAR(2)), 2) +
'01'
AS DATETIME) fulldate
from yourtable
) t
group by my, fulldate
order by fulldate
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set #query = 'SELECT name, ' + #cols + '
from
(
select name,
left(datename(month, dateadd(month, month, 0) -1), 3) +''_''+right(cast(year as varchar(4)), 2) MY,
[count]
from yourtable
) x
pivot
(
sum(count)
for my in (' + #cols + ')
) p '
execute(#query)
See SQL Fiddle with Demo.
This difference with this and the static version is if you need an unknown number of dates or want this to automatically update with new dates when they are available, this will return the new data without changing the code.
The result of both queries is:
| NAME | DEC_12 | JAN_13 | FEB_13 |
-----------------------------------
| xxx | 24 | 42 | 23 |
| yyy | 34 | 12 | 54 |

Answer 2

Try this:
WITH CTE
AS
(
SELECT
Name,
CAST(Month AS VARCHAR(2)) + '-' + CAST(Year AS VARCHAR(4)) AS MonthYear,
[Count]
FROM tablename
)
SELECT
Name,
[12-2012] AS 'Dec-12',
[1-2013] AS 'Jan-13',
[2-2013] AS 'Feb-13'
FROM CTE
PIVOT
(
MAX([Count])
FOR MonthYear IN([12-2012],
[1-2013],
[2-2013])
) AS p;
SQL Fiddle Demo

Answer 3

SELECT t.name
, MAX(CASE
WHEN t.month=12 AND t.year = 2012
THEN count
ELSE NULL
END) AS "Dec_12"
, MAX(CASE
WHEN t.month=1 AND t.year = 2013
THEN count
ELSE NULL
END) AS "Jan_13"
, MAX(CASE
WHEN t.month=2 AND t.year = 2013
THEN count
ELSE NULL
END) AS "Feb_13"
FROM table t
GROUP BY t.name
;